Synopsis

A careless moment leads Shizuka to swallow her mother’s opal, a gem valued at five hundred thousand yen. To retrieve it, Doraemon and Nobita deploy the miniature submarine from the fortieth episode, venturing inside her to locate the lost treasure. However, their efforts take an unexpected turn when a playful jest results in Nobita inadvertently swallowing an eraser, necessitating a return mission to recover it.