Magnum, P.I. - Season 6 Episode 12 -

An old comrade of Higgins' brings his travelling carnival to Hawaii. But when one of the performers is fatally stabbed, Higgins asks Thomas to investigate. Working undercover as a carnival 'roustabout', aided by Rick, Thomas learns that even before the killing, the carnival had been experiencing a string of 'accidents', and must pin-point exactly who is trying to force the show out of business...