Canna III is a water planet with a single large island. The island is bordered by a high cliff. Civilians irrigating the land has caused issues where soil and bedrock meet. The land has been turned into a saltwater swamp, turned upside down. The swamp is sliding into the ocean, taking inhabitable land with it. Compounding the problem is a fuel leak from underground tanks threatening to detonate. Two Colonial Survey troubleshooters have been called to the planet to try and rectify the situation.

Murray Leinster was the pen name of William Fitzgerald Jenkins, an American writer of genre fiction, particularly science fiction. He wrote and published more than 1,500 short stories and articles, 14 movie scripts, and hundreds of radio scripts and television plays.