When his father dies, Dave Owen, an ex-Royal Navy diver, inherits the family businesses and becomes a millionaire overnight. One of the businesses is Angling Charters, to which Dave adds commercial Diving. He is joined later by Joe, who was a Navy diver friend, and together they establish a diving company, but Dave has secrets he cannot share. His mother died very young, and his sister was murdered. All about them believe they know who the murderer is, but there is no actual proof that the man is the culprit, nor of many other unsolved crimes in the area. Dave takes in a tenant to occupy the Garden Flat below his house. She is suffering severe mental stress after a brutal sexual assault by the same man suspected of murdering Dave's sister. Running between Dave's workshop and his house is a tunnel that no one, other than Dave, knows exists. It is an old smugglers' tunnel, and is filled with contraband, stored there by an ancestor and later abandoned by him about a hundred years ago, when the ancestor decided to move to Kenya to seek a second fortune when he thought the Revenue was closing in on him. Dave and Joe are drawn into various situations of imposed violence, but are more than big enough, physically and mentally, to take care of whatever comes along.