Lieutenant Mike Conovan (Van Johnson), head of an Los Angeles Police Department homicide detective squad, investigates when Ed Monigan, an older member of his squad (and former partner), is murdered while off-duty and carrying $1,000 in cash. Conovan's current partner and one-time mentor, Fred Piper (John McIntire), is getting on in years and his eyesight is failing, while under Conovan's wing is rookie detective "C.C." (for "carbon copy") Gordon (Tom Drake), learning the ropes.