A ship called the Camara is sailing through the Irish Sea in 1826. The crew have put a large rock into a net and are hoisting it overboard. The Captain discovers what's happening and declares that they're "too close to land to let loose the demon". One of the crew members runs toward the stone and pushes it overboard, dying the second he touches it. With a loud splash, the rock falls into the water and sinks into the ocean.
Over a century later, the Seventh Doctor is enjoying a summer day at Blackpool with Ace. The Doctor is sitting in a beach chair near the water while he reads the Camara's ship log and a local newspaper with the headline "Seaside Kidnappings". Meanwhile, Ace is with a crowd watching a building that has caught on fire.
The Doctor notices something coming out of the sea and tells nearby beach-goers to get away from the water. A humanoid creature made of sand emerges from the waves, grabs a hot dog vendor close to the water and sucks the life out of him. As everyone else runs away from the beach, Ace comes down from the boardwalk to see. She grabs a surfboard and stabs the creature with it, but it has no effect. Back on the boardwalk, firefighters have came to save the burning building. The Doctor asks them for help and they spray the sand monster with their hoses.
After the monster melts into a pile of sand, the Doctor explains what it is. It's an Ogri that became sand after years of being eroded by the ocean. Recently, it kidnapped several people along the coast and used their bones to give itself structure. It was attracted to Blackpool by the heat from the burning building.
As the Doctor puts the Ogri into a pail and explains that Ogri are very susceptible to extreme heat. He then solves two problems at once by pouring the Ogri into the fire, killing the Ogri and putting out the fire.
- Ace wishes that she had her Nitro-9.