Mr. Happy gets Flushed Away

Mr. Happy Gets Flushed Away is a upcoming Mr. Men/Aardman crossover film, it will appear on Google Drive in the future.

Plot
Roddy St. James is an upper class pet rat who makes his home in a posh Kensington flat. While his owners are away on holiday, a common sewer rat named Sid comes spewing out of the sink and decides to stay, especially as England is playing against Germany in the World Cup Final. Roddy schemes to get rid of Sid by luring him into the toilet, but Sid is not fooled, instead throwing Roddy in and flushing him away into the sewer.

Roddy discovers a city resembling London, Ratropolis, made out of various bits of junk, and meets Rita Malone, an enterprising scavenger rat who works the drains in her faithful boat, the Jammy Dodger. Rita is irritated by Roddy initially, but ends up taking him along. Her archenemy The Toad sends his rat henchmen, Spike and Whitey, after her for stealing back her father's prized ruby. The Toad loathes all rodents, and plans to have Roddy and Rita frozen with liquid nitrogen inside an icemaker. The pair escape, and Rita takes a unique electrical cable that is required to control Ratropolis' floodgates.

Roddy discovers that the ruby is a fake and breaks it in front of Rita. Enraged, Rita tries to attack Roddy, but eventually calms down and explains that she is only angry because her father (quite literally) broke every bone in his body trying to obtain it just for her to find that it was just a worthless fake. Roddy offers Rita a real ruby if she takes him back to Kensington, to which she agrees, and the pair first stop to visit her family before setting off. During Roddy's stay, he overhears a conversation that causes him to think that Rita is selling him to The Toad, so he reneges on the deal and steals the Jammy Dodger. When Rita catches up to him, she is able to clear up the misunderstanding. The pair evade a pursuit from Spike, Whitey, and their accomplices, and incensed at his minions' repeated failures, The Toad sends for his French cousin, known as Le Frog. It is revealed that The Toad was Prince Charles' favorite childhood pet until he was abruptly replaced by a pet rat and subsequently flushed down a toilet, resulting in his hatred of rodents. Le Frog and his subordinates intercept Roddy and Rita and retrieve the cable, sinking the Jammy Dodger in the process, but the duo use a plastic bag to lift themselves out of the sewer and back to Roddy's home.

Roddy pays Rita the promised ruby and an emerald, then shows her around his house. She at first believes he has family in the home, but notices his cage and realizes he is a pet. Rita tries to persuade Roddy to come with her, but he is too proud to admit that he is lonely. She departs, but is soon captured by The Toad. Talking to Sid about half-time, Roddy pieces together The Toad's plan: to open the gates during halftime of the World Cup, when all the humans will most likely be using their toilets. As a result, a great sewage flood will form and drown Ratropolis in sewage, allowing The Toad to use the city as a home for his tadpole offspring. Roddy gives Sid his cushy position and has Sid flush him back to the sewers. He frees Rita, and together they defeat The Toad and his henchmen and freeze the wave of sewage with his liquid nitrogen.

Rita and Roddy build the Jammy Dodger Mark II and set off in her while Le Frog and his men hitchhike back to France.

In a mid-credits scene, Roddy's former owner Tabitha returns home with a new pet cat, which scares Sid.