Hogan and Onyx are training at the Coast Guard's National Ice Rescue School in Essexville, Michigan, when their instructor receives an urgent call about a snowmobiler who has fallen through the ice. There is no time to waste, and Hogan, Onyx, and the rest of the trainees must get to work right away. When the Coasties reach the man in distress, it is clear he is suffering from hypothermia. The team must act quickly. But the spring ice is too thin, and when Hogan tries to reach the man, the ice beneath him gives way. The ice is too weak to support Hogan or any of the other Coasties, except for one-Onyx the miracle dog!