In 1947 Chicago, detective Eliot Ness (Robert Stack) comes out of retirement after the murder of Martin Labine (Frank Adamson), a former cop suspected of Mafia connections. As an old colleague, Ness takes the case extremely personally, and makes it his sole mission to track down whoever's responsible for the crime. Along the way, Ness partners with Labine's son, Gil (Jack Coleman), as they delve into the Mafia. Meanwhile, the two have to avoid ending up casualties in the ongoing gang war.