In the deep waters of the Great Blue Sea lives Oscar, a plump little fish. Despite his size, Oscar is very shy. That's why he only comes out of his cave at night, when the other fish are asleep.

One night, Oscar discovers that Stanley, the meanest and rudest octopus, has something that Oscar wants to borrow, but he is too embarrassed and scared to ask for it. The dilemma is great...

Unfortunately, with his choice, Oscar found himself in "deep waters" and got his housemates in trouble! Will he find the courage to take responsibility and save the sea?