Evelyn begins telling a story to one of her students, Sally, about a 19th century sea adventure she has taken with the Doctor.

In the story they travel to the Ruby Islands (where precious gems are buried) together with their crew and the pirates.

Evelyn is profoundly upset when she is unable to stop the murderous pirate captain, Red Jasper, from beating a cabin boy to death.

To help her student Evelyn and the Doctor to travel back in time to dissuade Sally from killing herself, showing her that she is loved.

Music from more of the Savoy operas is used elsewhere in it, such as one of the pirates humming "Rising Early in the Morning" from The Gondoliers.