Doraemon's magic gadgets finally meet a mystery that can't be solved by just pulling something out of a pocket. Nobita and the crew crash-land on an island where the animals talk, the rules are backwards, and every invention either saves them or makes things worse in ways that actually matter. You get the chaos and heart of early Doraemon, the kind where a kid's bad luck and a robot's endless optimism somehow keep people alive, without it feeling like filler.

Nobita and his dad buy a large rhinoceros beetle, and Nobita promises his dad he will look after it well. Later, Doraemon and his friends discover a strange island where a tribe lives alongside prehistoric creatures long thought to be extinct. Those animals survive thanks to a mythical beetle spirit known as Golden Hercules. Trouble arrives in the form of criminals from the future who want to capture Golden Hercules and profit from it, and Doraemon's group has to deal with them. The film mixes adventure, comedy and fantasy.