A bomb under a nightclub provides 347 Section with an opportunity for a little recreation. Ash admits that he is smitten with Susan.

Ash works on a bomb outside a destroyed office building while the men of 347 Section try to rescue a woman trapped inside and with another bomb right beside her.

Newly-promoted Major Francis takes command of the unit and proceeds to enforce new disciplines, but his chief target seems to be Ash and his men.

347 Section cooperates with the Royal Navy to deal with a bomb that has a 17-second fuse. Ash decides to ask Susan to marry him.

Ash is assigned to Cambridge to help Dr. Gillespie with the new Y fuse, and meets Susan again.

The Company packs up and moves to the coast where they are to clear the beaches of dozens of British mines laid in preparation for a German invasion.

Ash convalesces after a near-fatal accident while defusing a mine. With his mobility severely impaired, he is to be reassigned to light duties away from the bomb disposal unit.