Live-action version of the popular 70's japanese manga and anime, Dokonjô Gaeru. In this version, Hiroshi, Kyôko, and the rest of the classmates are 30 years old. The setting is modern day Japan, and of course, Hiroshi still wears Pyonkichi (aka Raponchi) on his shirt.
It was 16 years ago. Hiroshi, a clumsy middle schooler, tripped at the park and fell on top of a frog. Splat! The frog was flattened. But wait. The flat frog got stuck on his shirt and, even stranger, started to speak!