Joe Mannix is visited by Portia and Penelope Penhaven, two elderly, eccentric sisters who insist that Mannix investigate a hit-and-run earlier that day, which damaged one of the headlights on their ancient automobile. Amused by their request, and overborne by Portia's forceful personality, Mannix agrees to look into the matter, but discovers that the vehicle that hit them was taken from a rental lot, apparently without the knowledge of the lot's owner. Digging deeper, however, Mannix soon discovers that the hit-and-run might be related to a murder committed nor far away on that same day.
—aldanoli