To this end, he has been defying his grandfather's admonishments and has been straying from the huge cave and exploring the surrounding areas, finding all sorts of "treasures" left behind by human littering. When Kraken discovers this, he blows a gasket and declares that Deep will never be fit to rule the community in his place if he doesn't grow up, but Deep persists with his nonsense and in fooling around with something he shouldn't have, ends up trapping (almost) everyone in the cave when he inadvertently causes an explosion that threatens the existence of everyone living in the cave. Fortunately, Deep had convinced his best friends Evo (Stephen Hughes), a frightened lantern fish, and Alice (Lindsey Alena), a plucky shrimp, to come exploring with him and they are all on the outside, but can't help by themselves. Kraken sends Deep off to locate his old friend Nathan (Lewis Macleod), a large whale, as he is the only one who could possibly remove the large rock trapping them all inside. But Deep must act quickly as lava is pouring into the cave and they won't last long.
As they journey towards the City of Men, where Kraken last saw Nathan, the trio will encounter many frightening and fascinating things, including the sunken Titanic ocean liner, which is now home to lots of skeletons and a creepy singing vampire octopus (is that a thing?) named Norma (Anna Vocino), who is desperate for a new audience and a love interest. They next encounter a hungry and lonely eel named Maura (Elizabeth Gray) who really wants to eat them, but also really wants some friends. Priorities, am I right?
Before long, they encounter a gang of singing crabs in New York, a toxic waste-fueled horde of murderous zombie fish, and a trio of animal scientists with the promise of salvation. But can they be trusted? Besides, they need to stay on task and find Nathan if their families are to be saved, but when you are a little yellow octopus out to prove yourself, the world can be a dangerous place.
Deep is a cute movie with a few musical tunes, one of which is included as a karaoke sing-along as a special feature, and kids will probably like it, but it does have some creepy scenes, so it's probably not one for really young kids. I don't know if it is one that kids will watch over and over, but the animations are pretty and the characters are enjoyable.