Cindy Lou Who is a sweet young girl from Whoville, one of the main characters and the deuteragonist of the computer-animated Dr. Seuss' The Grinch.
She's voiced by Cameron Seely who was in the movie The Greatest Showman.
This version of Cindy Lou Who is different than her 1966 and 2000 version. For example, Cindy-Lou Who plots to capture Santa Claus to thank him for helping her single mother every Christmas which it will interfere with The Grinch's plans.
Like her previous version, she does love Christmas. But her single mother have been working so hard with her and her twins brothers. So, she decided to write a letter to Santa by wishing that she want her mother to be happy and spending time with them on Christmas.
She's very sweet, kind, helpful and very fun loving person who cares about others than herself. Like any daughter, she love her family and want to make sure that her mom is still happy on Christmas. Unlike her 2000 version, she never mention about her father since he wasn't never seen. Also, she's the first person who hug the Grinch (kind of similar to her live action countpart when Cindy Lou gave Grinch a kiss on the cheek after he redeemed himself).
While the Grinch was shopping for foods, Cindy Lou Who have always noticed that her mother Donna is overworked by trying to take care of herself and her twin infant brothers, Buster and Bean.
She decides to send a letter to Santa Claus to help her mother at first, but after encountering the Grinch, who sarcastically says that she'll have to talk to Santa face-to-face about it, she decides to try and trap Santa with the help of her friends.
With Christmas just around the corner, all the Whoville festivities force the Grinch to recall his sad childhood spent mostly alone and unwanted in a run down orphanage.
The Grinch soon decides that he'll steal Christmas from Whoville to assuage his distress and acquires a fat reindeer whom he calls Fred to help him pull a sleigh that he stole from his neighbor, Mr. Bricklebaum. After a test run, the Grinch discovers that Fred has a wife and child. With a heavy heart, he lets Fred go back to them.
On Christmas Eve, Cindy Lou and her mother were talking about what Cindy Lou want for Christmas which Cindy Lou told her that she's not telling, but she know that whatever she want, it make them very happy. After her mother went to bed, she quietly set a trap so she can finally see Santa Claus and talk with him.
Meanwhile, after making a Santa Claus disguise and dozens of gadgets to help him with his theft, the Grinch and Max, who pulls the sleigh in Fred's place, go down to Whoville and begin stealing the decorations and presents.
He soon encounters Cindy after falling into her trap and Cindy told him that she doesn't want presents because she want to help her mom on Christmas since she know that her mom always working so hard and want her to be happy.
Her request is to help lighten her mother's workload and her kind advice about listening to the Whos' singing to take his sadness away, touches the Grinch's bitter heart and Cindy hug the Grinch which the Grinch was shocked and surprised that he never got hug before. She also told him "Thank you, Santa. Good night" and she went back to bed. Nevertheless, the Grinch carries on with his mission.
After stealing every Christmas present and decorations, the Grinch and Max head back to Mount Crumpit to dispose of them. The Whos wake up and are shocked to see that the presents and decorations are gone.
Then, Cindy Lou realize that it was her fault because she caught Santa and thinks that she made him mad by taking away their Christmas, but Donna tells her that Christmas is more than just presents and that Cindy Lou's the best thing that ever happened to her which it make Cindy Lou really happy. Later, the Whos join together by singing Welcome Christmas.
Then, the Grinch and Max heard the singing down in Whoville before the Grinch dump the sleigh which the Grinch is puzzled to see that they're celebrating Christmas without presents, despite his theft.
After remembering Cindy Lou's advice and listening to their song, his small heart triples in size, causing him to double over into breathless joy and wonder. Then,the sleigh almost falls off Mount Crumpit and the Grinch tries to save it. In the nick of time, Fred and his family come to his aid.
After securing the sleigh, the Grinch and Max go back to Whoville to return the stolen items and admits his theft to the Whos and apologizes before going back to his cave. Feeling sorry for the Grinch, Cindy Lou comes to his house and invite him to celebrate Christmas at her house since she forgave him and told him that no one should be alone on Christmas which it surprised the Grinch.
Then, The Grinch awkwardly attends since he haven't been invited before and Cindy Lou was very happy that he came and want him to feel welcome. When seated down for dinner, The Grinch confesses that it wasn't really Christmas he disliked, but being lonely and his bitterness over being neglected. He also thank Cindy Lou for changing his life, because of her kindness and her mother hug Cindy Lou by saying that's my girl.
Then, Cindy smiles and wish the Grinch a merry Christmas which the Grinch smiles and wish her a merry Christmas too. Before carving the roast beast, the Grinch offers a toast, "To kindness and love, the things we need most."