Synopsis

Trouble finds Nobita when his mother discovers a failed test paper hidden in his drawer. Desperate for a solution, he turns to Doraemon, who offers him a special key capable of locking anything. The ingenious mechanism allows only the user to secure or release the lock, activated by the phrases "Open Sesame" and "Close Sesame." However, the episode concludes with Nobita locked out in the downpour; a lingering cold has altered his voice, rendering the key unresponsive to his commands.