Hound is returning to England, but while crossing the English Channel, the ship he's on is attacked by pirates who are after one of the passengers. With the aid of another passenger, Dr. John Watson, Hound attempts to save the day.

An aristocrat's son is the main suspect after a crown on loan from the Queen goes missing. Hound is asked to investigate, not knowing Professor Moriarty has been watching the location.

A mysterious green balloon lands in Hound's backyard, with a message asking for help as the sender is being held prisoner on Dolphin Island.

Moriarty succeeds in stealing a large gold statue, but Hound is able to track his escape, learning that Moriarty hid it somewhere by the docks, and must find it before Moriarty returns.

Moriarty and his gang manage to steal a shipment of gold, but Inspector Lestrade's investigation is making it difficult for the gang to get the gold out of London. Meanwhile, Hound and Watson investigates an odd break-in and robbery at a company making a new blimp.

There's a new thief in London, one that puts Moriarty to shame, and their next target appears to be the Queen's favorite horse.

Moriarty enters a prestigious airplane race, with the intent of sabotaging his way into first place, including stealing parts from other entrants to make his plane the best. Mrs. Hudson, Hound and Watson enter the race in hopes of stopping him.

When Moriarty goes to great lengths to steal a parrot off a train, Hound takes up the case to find out what's so special about this parrot.

Moriarty is after a large diamond, but after hiding it in a doll, he ends up with more than he bargained for.