Tentacles has grown up different from most other giant squid. Instead of exploring the open waters of the mysterious, deep ocean realm, he has been secretly left in the charge of three tiny fish in the hopes that they will protect him from a dangerous band of sperm whales who are determined to take over the region. Tentacles has never seen a whale, or a sea monster, or even another giant squid before, but this quickly changes when he and his three small caretakers embark on a daring journey to reach the last safe place in the region, – a hidden, deep ocean palace.
Once there, Tentacles can grow in safety, while he prepares to face the whales. But the open waters are far more dangerous than he realizes. Tentacles not only stumbles across secret tunnels and hidden sea monsters, but may also find the story behind his own mysterious upbringing.