Great Oak gets ill.
Bobweb decides to take control of the Thunderbottom.
Siren's sister is kidnapped.
The crew looks after Aqua, the baby seahorse; Jake and Bobweb seek stolen treasure.
An unlucky Albatross visits the crew.
Captain Jake's cat goes undercover.
Captain Abercromby must fight his first duel.
Sailor of the Year competition causes some tension.