Colonel Lyle C. Rumford, the proud Commandant of a military academy, is incensed that William Haynes, the owner of the property, wants to turn it into a co-ed college. Rumford plots to kill Haynes by tampering with the cannon that Haynes is due to fire in a ceremony. The cannon is set to backfire, thereby making the explosion seem an unfortunate accident caused by a clumsy attendant. Los Angeles Police Department's Lt. Columbo comes to the academy to investigate Haynes' death and instantly suspects that Rumford had something to do with the explosion, which Columbo believes was not accidental. Stars Peter Falk.