A Rough Guide

HMS Pinafore is anchored off Portsmouth.  Little Buttercup is selling her wares to the crew.  A crewman, Ralph Rackstraw is in love with the Captain's daughter, Josephine, who unbeknownst to him returns his affections.

But Josephine is promised to Sir Joseph Porter.  In desperation Ralph declares his love but is rejected and decides to end it all.  He is prevented from doing so by Josephine who, at last tells Ralph of her love for him.

All seems to be going wrong for the Captain, with Sir Joseph a plan is concocted for him to win Josephine but this backfires and Josephine and Ralph make plans to elope.

The Captain and the unpleasant Dick Deadeye manage to foil this plan.  But in his anger the Captain curses!  Sir Joseph overhears and sends the Captain to his cabin.

At this point Buttercup reveals that in fact the Captain and Ralph were swapped at birth.   And with a bound everyone is free to marry their chosen partner!