"Berkeley and her best friend, Garth, live on an old cruise ship, scavenging for supplies from the drowned cities left behind on the ocean floor after the sea swallowed up all the land. They think they've seen every kind of aquatic creature, but they never expected to find sea monsters... After awakening a Hydra, Berkeley and Garth are sent to live on a submarine, where they study and hunt sea monsters. But the Hydra wants revenge on their home ship--and...

When seventeen-year-old friends Liv and Will are accepted in a semester-at-sea program, they are excited to spend six weeks aboard the luxury cruise ship The Eos, but after Will disappears the first night, Liv grows suspicious that something sinister is lurking below deck.

"All aboard the mermaid cruise ship! Gabby sets sail with MerCat for an adventure at sea. Will they have an a-meow-zing time at the mermaid cove?"--

After surviving the earthquake and tsunami, Shy manages to make it back to land, but he's far from safe because a secret his cruise ship coworker Addie shared with him is one that people have killed for, and now that Shy knows, he's become a moving target.

After an earthquake destroys California and a tsunami wrecks the luxury cruise ship where he is a summer employee, high schooler Shy confronts another deadly surprise.

While on a cruise with their grandfather, the Alden children help discover who is behind the mysterious troubles of the ship--disconnected phone lines, engine trouble, a man overboard--and still have fun sightseeing, eating, and swimming.

The Water Sprites are supposed to perform their medal-winning synchronized swimming routine aboard a cruise ship, but everything goes wrong when the piglets aboard start throwing things at the swimmers--so Gracie enlists the help of famous Rita Sinclair and her dancers to help impose order on the unruly passengers.

Nancy, Bess, and George are on a cruise ship tour of Alaska, and the cruise director needs Nancy's help when strange things keep happening.

In 1889, the ship Etruria departs Liverpool, England, for New York carrying Audrey Rose Wadsworth and her crime-solving partner, Thomas, a famous escape artist, and a cold-blooded killer.

The Ghost Gang is invited to record onboard a haunted cruise ship.