One year after the Diary of a Wimpy Kid: Dog Days (film), while at the Corny's family restaurant, the Heffley family — consists of Greg Heffley, Rodrick, Frank, Susan and Manny — plans to take a road trip across the USA to attend Meemaw's 90th birthday. However, after Greg and Rowley rescue his younger brother Manny, who got stuck inside a tube in the play area, Greg ends up in a ball pit with a diaper stuck on his hand, startling him. He subsequently becomes famous after the people around him record him and post the footage on the internet, leading Greg to be dubbed as "Diaper Hands", much to Greg's devastation.

Scott Lang and Hope Van Dyne are dragged into the Quantum Realm, along with Hope's parents and Scott's daughter Cassie. Together they must find a way to escape, but what secrets is Hope's mother hiding? And who is the mysterious Kang?

Armed with a super-suit with the astonishing ability to shrink in scale but increase in strength, cat burglar Scott Lang must embrace his inner hero and help his mentor, Dr. Hank Pym, pull off a plan that will save the world.

High schooler Greg, who spends most of his time making parodies of classic movies with his co-worker Earl, finds his outlook forever altered after befriending a classmate who has just been diagnosed with cancer.

Georgie, a dreamy 12-year-old girl, lives happily alone in her London flat, filling it with magic. Suddenly, her estranged father turns up and forces her to confront reality.

As Scott Lang balances being both a superhero and a father, Hope van Dyne and Dr. Hank Pym present an urgent new mission that finds the Ant-Man fighting alongside The Wasp to uncover secrets from their past.