One

Dashi and Shellington have always been close friends, right from the start of the Octonauts. So when Dashi is attacked by cone snails and is hit by the horrible after-effects, Shellington decides it's his duty-along with a certain green bunny-to look after her.
Long chats, sleepovers and surprise visits from cousins make up the next few weeks. But as Dashi and 'Shel' spend more time together, they begin to question their feelings towards each other.
Because both secretly want to be more than friends with each other.
But will they be brave enough to admit their feelings?