The first scene is inside the IRA where a man is going over taxes. I recognized his voice immediately. It's a very young Dan Frazier, who went on to become Telly Savalas' boss in the "Kojak" series on TV. Anyway, Frazier ("Tom Elliot," in here) and his secretary are wrapping up the 1953 taxes of people. The name "Bilko" gets investigated instead of "Billings" when a secretary carelessly hands the wrong folder to another worker. Bilko gets the IRA notice, panics and goes down to the office the next day. By opening his big mouth and divulging a few things he shouldn't have before giving the tax men a chance to explain their error, the sergeant is now going to be audited.
How he tries to get out of it, and the lengths he and his men go to with tons of paperwork and the verification of party gifts (which he never gave) is the story of this episode, which has a few good moments but nothing extraordinary.