In the first episode, we follow Senior Investigator Mark as he is alerted to an incident on the River Mersey where a crew member of a tug boat has sadly died. Meanwhile, in Shetland, a Mayday call is picked up from a sinking fishing vessel and on the south coast in Dorset, our Coastguard Rescue Teams and a Coastguard helicopter are sent to an elderly man who finds himself in serious danger after getting stuck in the mud. The fixed wing aircraft spots a fisherman putting himself in danger, much to the dismay of the vessel’s skipper.