The Octonauts follow a trail of deep-sea debris to its source: a derelict ship floating unmanned on the surface. But the ship seems to be haunted by ghostly voices, which a quick dip below the water line reveals to be hundreds of barnacles stuck to the ship. As the ship drifts into waters too cold for the barnacles, the Octonauts must find a way to tow it to warmer waters before it sinks or falls apart.

The show’s own verdict is on its page.