Dawn is bummed when an injury prevents her from joining the Croods and Bettermans to a trip to Fizzy Falls, but when Thunk recruits her on his quest for an ancient stash of legendary snacks.

Grug accidentally reveals a subterranean cave beneath the treehouse. When Phil can't convince Hope, Grug, and Ugga that the treehouse is more impressive than the new cave, he sets out to destroy the cave.