The film will be co-directed by Rich Moore and John Lasseter.
Elias E. Mortimer, the creator of the Thrillville theme parks, is getting all worn out from the past 50 years of designing exciting roller coasters and carnival rides. The parks themselves are losing guests to a rival theme park, Glob-O-Joy.
Meanwhile, his nephew Harry Stevenson has graduated from college, and needs a job to kick off his career. Mortimer steps in and requests his help, because his coaster designs are just what Thrillville needs. But instead of having Harry sit in an office filing paperwork, he puts him in right in the middle of the action so he can interact with guests and oversee every new project.
On the job, Harry meets Emma Smith, a girl who rarely ever has fun, and her younger brother John, a video game enthusiast. They become his closest friends as they begin to share experiences together. But when Glob-O-Joy's CEO, G. Gilbert Garrison, threatens to put Thrillville out of business for good, they must put their designing skills to the test to save the theme parks they love most.
- Ryan Reynolds as Harry Stevenson
- Odeya Rush as Emma Smith
- Grant Palmer as John Smith
- Brian Greene as Elias E. Mortimer
- Rob Paulsen as G. Gilbert Garrison