Casper the friendly ghost have meet Crystal the Unsinging little angel who have a same problem as Casper the Friendly Ghost, they and their humans friends have the courage to try.
Once upon a time at Whipstaff Manor, Casper and his human girlfriend, Kat Harvey were going out on a nature walk on the mountain. Then suddenly, Kibosh's sidekick, Snivel came and warned that there is a 12 year old girl named Hannah who doesn't have any friends and Kat realize that she had a same problem as she does before she and her dad, Dr. James Harvey meet Casper and his uncles, Fatso, Stinkie and Stretch the Ghostly Trios, so Casper and Kat decided to find Hannah and be their friend, but Snivel said to them that she love her father because they are always best friends, now her father died its just her and her mother, Grace Haines in Paris. But Kat told Snivel that Paris is in France and it is in Europe and they're in America. Snivel told the kids that Casper's horse, Nightmare can give them a ride and so Nightmare came and Casper and Kat get on her back and begin to fly to Paris.
During this, above the clouds of heaven there were pretty Angels and all of the little angels have to go to school to learn to sing with their hearts and when they grown up, they'll give some birth to some babies, but not all angels can sing, when a 5 year old little angel, Crystal try to sing, her voice keep breaking everything if she tried to sing. Crystal's teacher call her two aunts, Ruby and Emerald the Double Angels and told them that their niece is not a very good singer because she kept breaking everything if she tried to sing. The Double Angels told Crystal's teacher that they will have to work on her, after the Angels school Crystal told her aunts, why is her singing voice kept breaking if she tried to sing, the Double Angels told her that will hurt everything including everyone else ears, but the Double Angels have an idea instead letting Crystal sing, they'll give her the harp instrument, they've been saving it for her birthday, the Double Angels told Crystal that can play with the harp of the music so it won't do the same thing what Crystal's voice does.
Meanwhile, when Crystal was playing with her harp, she see something down in Paris, and it was two people and they are mother and her 12 year old girl named Grace and Hannah Haines. Grace told her daughter that after her father died, she decided to learn something new and she wants Hannah to become academy graduates because Grace decided a better plan in Paris. Grace show Hannah a strategy for hours on the day, day of the week and much more, Grace told Hannah to follow the strategy to show her what to do, if she pass she'll act like a wonderful grownup. When Grace left for work, Hannah begin her grownup steady work, Crystal with her harp fly down from heaven and come to see her, Crystal sneak in the house and watch Hannah proactive her steady work when she made a sound, Hannah have hard what Crystal made, so Hannah look everywhere in her house until she see a little blue angel, so she got faithed and Crystal was shocked so she fly back outside.
Moment later, when Hannah wake up, she see the angel have disappeared and Crystal was watching her continue with her steady work until something came from the sky, it was Casper, Kat and Nightmare made their way to Paris. They landed near Hannah's house and they meet the Unsinging little angel and she didn't realize that a ghost is not so scary all. Casper told Crystal that he is a friendly ghost and he wants to make friends with anyone, but his uncles are scary and all they want to do is scared people. He also told her that he and Kat are sent to help Hannah Haines, but Crystal told them that they are right next to her house and they made it. When Grace got home from work, Hannah told her mother that she saw a little girl with a ring on her head and blue wings and blue dress, but Grace is having a hard time believing that because it's a little kids things and Hannah have to learn grownup things, and Casper, Kat and Crystal are being listed. Kat told Crystal that she and her father believe in ghosts and they think the spirits are real, so Casper, Kat and Crystal can provide Hannah and show her that Angels and ghosts are real.
One morning, Grace told her daughter to practice her steady work and then she left. When Hannah follow the strategy, she hard a door bell ring and it was Kat Harvey, who told her that she had a same problem as she does, so Hannah invited her in. After Hannah offer Kat some drink, Kat begin to tell her if she believed in spirit, but Hannah thought those spirits are children things, but Kat told her that she and her father believe in ghosts, and she calls Casper to come in and he did. When Hannah jump up and she was scared, Kat said to her to calm down and told her that Casper is a friendly ghost and she and her dad lived with him and his uncles at Whipstaff Manor. Kat told Hannah that there's another spirit that she wanted to see in her closet and she did. When Hannah open her closet, it was a little angel and Hannah was right. Crystal show Hannah that she came from heaven and she lived up there with her two aunts. Hannah have begin to like her three new friends, so one of them would like to help her with her grownup steady.
Meanwhile, Crystal told Hannah that she can't sing because if she tried to sing, she kept breaking everything and that why she has the harp to play the music to help her and Hannah understand that. Casper and Kat are looking at the strategy to know what are hour of the day after the day of the week and much more than suddenly, Kibosh appeared and he is checking on Casper and Kat, they told him that they are helping Hannah with the grownup steady and they are making comfortable with her. But Kibosh told Casper and Kat that Dr. Harvey and the Ghostly Trios are so worried about them because they were waiting for them to come back to America. But Casper told him that he and Kat are trying to make Hannah happy, and they also want her mother to believe her because she doesn't believe in spirits. Kibosh was shocked because nobody else believes in spirits he had something to prove it to Grace and so he left.
At the other places in France, there was a naughty man named Jean Moris and his plan to close down the mortgage at The Haines house, but first he have to meet Grace Haines and tell her that she must sign the contract to move her and her daughter to the new house, so Jean Moris can change the house and he is buried down and nothing else can stop him. When Jean Moris came to Paris he finally meet Grace and told her that he is closing down the mortgage at her home in three days, but Grace told him that he had a daughter and she was trained to be academy graduates. Jean Moris said to her if she doesn't sign the contract, Grace and her daughter will die just like her husband.
Back at the Haines House, Casper, Kat and Crystal have finished Hannah steady work and she loves it. After that, Grace have come home from work, so Casper and Crystal have to hide, while Kat can be interduce as Hannah's new friend. After Grace come in the house, Hannah interduce her mother to her new friend, Kat Harvey, but Grace have told Hannah, that she met a man who is closing down the mortgage at their home. If Grace and Hannah can't sign the contract they'll died just like Mr. Haines as Casper and Crystal are being listed. Crystal told Casper that she always knows someone whose can help Hannah and Grace save their home and those are the Double Angels. Crystal begin to play her her harp for her two aunts to came and they did, she and Casper told them everything. The Double Angels can save the Haines house at no time.
Later that night, Casper and Crystal told Kat and Hannah that the Double Angels can save the house if they have to find money to pay Jean Moris back. Ruby told Casper, Kat, Crystal and Hannah that the first thing to do is sell lemonade and everyone in Paris by tomorrow and they all agree with that. That morning, after Grace left for work, Casper, Kat, Crystal and Hannah get started with the lemonade stand to set up lemonade cups and drink. Casper and Crystal have to vanish because everyone else will be afraid of ghosts and Angels. Then suddenly, Jean Moris came and see two teenage girls selling lemonade to everyone in Paris. Hannah told him that she and Kat are selling lemonade to save her house, but Jean Moris was shocked because Grace's daughter wants to save her home by finding money so he have to think of another way to get Haines out of France.
At Jean Moris's lare, he can't believe those girls are saying the Haines house to pay him back. So he begin to hire his two men, Jap and Nick to stop the girls before they save the house. Back at the Haines house, the Double Angels were helping Hannah's steady work until she, Casper, Kat and Crystal came with 50 dollars, Emerald told them that 50 more dollars in two days and the house is save. Then suddenly, Jap and Nick came near the house and decided to set trap. But the Double Angels have hard that someone outside are causing trouble and it was Jap and Nick, Casper told the Double Angels that he knows how to handle it, so he fly outside and scared Jap and Nick away so they won't stop Kat and Hannah from saving the house. Kat gave Casper a kiss for scary them away and so did Crystal and Hannah.
Back at Jean Moris's lare, Jap and Nick told their boss that they saw a real ghost and Jean Moris can't believe that there's a ghost at the Haines house. He thought of something, "A ghost don't want anyone to close down a mortgage." So his next plan to kidnap the Haines family as they go out for a mother and daughter time. But outside the lare, the Double Angels hard every word what Jean Moris said so they must warn Casper, Kat, Crystal and Hannah immediately.
That night at the Haines house, Hannah and Kat told Grace that they have 50 dollars to save the house. Grace didn't know how they ever do that, Hannah told her mother that she and Kat have an idea to save their home so they can pay Jean Moris back, but Grace told them that saving money is a lot thing to all but Hannah is supposed to do her steady work while Grace is out working. While Casper and Crystal are being listed, the Double Angels told them that Jean Moris is plotting to overthrow Grace and Hannah out of Paris and decided to kill them after Grace don't sign the contract in two days. Casper and Crystal can't believe that man is getting rid of the Haines family, so they must warn Kat and Hannah by tomorrow morning.
Meanwhile this morning, Grace have to go to work and she told Hannah to practice her steady work and not to goofy off again and she understand so her mother left. After Grace left for work, Casper and Crystal warn Kat and Hannah that Jean Moris is plotting to kill Hannah and her mother, Grace, the girls can't believe it because that man is trying to get rid of the Haines family. Hannah got an idea, she told the Double Angels manager her steady work while she, Casper, Kat and Crystal have to go stop Jean Moris and his men and if they are not back home, the Double Angels show Grace to provide if she believes in spirits and they agreed with it and so Casper, Kat, Crystal and Hannah left with Casper's horse, Nightmare.
As the kids fly with Nightmare, they made their way to Jean Moris's lare. Casper, Kat, Nightmare, Crystal and Hannah get behind the guarantee can, so anyone can't see them until one of them are gone, so they sneak inside of the lare. But Snivel show up and Casper told him to be quite because Jean Moris's men might hear them, then Casper told Snivel to join him, Kat, Nightmare, Crystal and Hannah to stop Jean Moris before he going to murderer Hannah and her mother. Then suddenly, Jap and Nick show up and begin to capture Casper, Kat, Crystal and Hannah, but Casper and Kat told Snivel to go get Dr. Harvey and the Ghostly Trios immediately while Nightmare fly back to the Haines house to warn the Double Angels.
That night, when Grace came home from work, she realized that her daughter is gone with a new friend, then suddenly Grace have hard two strange voice and it turns out to be the Double Angels, Grace didn't believe her eyes because those Angels are real. The Double Angels told her that the other day, her daughter saw a little girl with a ring on her head and have blue wings and wear blue dress, but Grace thought that was in Hannah imagination, but Ruby told her that a little girl Hannah saw was a little angel and it is the Double Angels niece and she had a same problem as Grace's daughter dose. Then suddenly, Nightmare show up and whisper in Emerald's ear that Jean Moris kidnapped Casper, Kat, Crystal and Hannah, but Grace didn't believe that Jean Moris is a bad man, so the Double Angels fly her to find his lare.
Later this morning, Jean Moris, Jap and Nick have tie Kat and Hannah to the chair, and trap Casper and Crystal in the giant jarred. Casper tell Jean Moris, "Why aren't you so scared of ghost." Jean Moris told him he always like to harms any spirits including ghost and angel. Kat told that Moris that he's not going to get a way with this, Jean Moris told her that he already had. After Jean Moris left the room, Casper and Kat hope if her dad and his uncles are arrived so they can free them, Crystal and Hannah. Then suddenly Kibosh show up and told the kids that Snivel told him that they are in peril by the evil fleshy, so Kibosh use his magic to bean Dr. James Harvey and the Ghostly Trios in Jean Moris's lare and he did.
After Kibosh brought Dr. Harvey and the Ghostly Trios to the lare, he told them that his daughter and their nephew are in peril by an evil fleshy, so he told them to free them immediately after Kibosh left. Dr. Harvey free Kat and Hannah from the chair and the Ghostly Trios free Casper and Crystal from the giant jarred. After that, Jean Moris came with Jap and Nick and realize American man and three more ghosts have free Casper, Kat, Crystal and Hannah so the battle is about to begin. But the Ghostly Trios use one of their powers to scare those evil fleshies, Stretch stretched his body to go around Jean Moris and his men, Stinkie used his smells to stink them, and Fatso throw every food to them. After that, Grace and the Double Angels came and they were glad that Crystal and Hannah are alright, then Grace stand up to Jean Moris and told him that deal is off. Then Jean Moris began to faith.
Moment Later, the French police arrested Jean Moris and his men for kidnapping Casper, Kat, Crystal and Hannah and also trying to close down the mortgage. Grace apologize to Hannah for not believing in her about the spirit thing after her father died and she forgive her mother. Kat interduce her father to Hannah and her mother and Casper interduce his uncles to Crystal and her aunts. The Ghostly Trios didn't knows that the ghosts and the angels are the same spirits, the Double Angels told them, when people die, they also turn into Angels managed to live up in heaven to watch the world and the Ghostly Trios understand that. Dr. Harvey told Grace and Hannah if they, Crystal and the Double Angels would like to come visit him, Kat Casper and the Ghostly Trios in America someday and they all would love to, and so Casper, Kat, Dr. Harvey and the Ghostly Trios wave goodbye to Crystal, Hannah, Grace and the Double Angels and head back home to Whipstaff Manor in America and everyone live happily ever after.