The Octonauts and the Kelp Monster Mystery

The Octonauts and the Kelp Monster Mystery is the 12th episode in the 4th series of Octonauts.

Plot synopsis
When a mother kelp snail's babies goes missing, Dashi brings her little sister, Koshi, to invesgative with her. When they find the baby snails, They find out that they were carried in the back of a gray whale!

Appearances

 * Gray Whale
 * Koshi
 * All Octonauts

Notes & trivia

 * This episode is the first and only appearence of Koshi.