Jack Frost is a gritty, dogged and unconventional detective with sympathy for the underdog and an instinct for moral justice who attracts trouble like a magnet. Despite some animosity with his superintendent, Norman “Horn-rimmed Harry” Mullett, Frost and his ever-changing roster of assistants manage to solve cases via his clever mind, good heart, and cool touch.
The first in the final two-part episode in the series sees Frost attempting to crack an illegal dog-fighting ring, only to discover that its manager, a wealthy Denton businessman, has links to a drug-smuggling operation. Frost also begins to form a relationship with RSPCA Inspector Christine Moorhead, and attempts to finally get over the death of his wife.
Frost considers retiring from the Police force and plans to get married, ending the series, however DS George Toolan dies of heart failure following a collision outside the church where the wedding is about to take place. It is noteworthy that an alternate ending was filmed, where Frost is killed instead of George, but David Jason chose the 'happier' ending over this one.