A salute to Seymour Skinner honoring his twentieth year as principal is interrupted by a stranger claiming to be the real Sergeant Seymour Skinner. Skinner admits to being an impostor, revealing that his real name is Armin Tamzarian, and that he is actually an orphan from Capital City that spent his youth as a "no-good street punk." After getting in trouble with the law, Tamzarian was sent to the army and shipped to Vietnam, where Sgt. Skinner took him under his wing.

When Sgt. Skinner was presumed dead after a mortar explosion, Tamzarian returned to Springfield, where he assumed the identity of Skinner and became the principal of Springfield Elementary. Exposed as a fraud, Tamzarian resigns his position, turning it over to Sgt. Skinner. As Sgt. Skinner assumes the role of son and principal, Tamzarian returns to being a lowlife in Capital City.

Soon, it becomes apparent that Springfield prefers the old Skinner to the new one. Agnes, Mrs. Krabappel, and the Simpsons travel to Capital City to bring Tamzarian back. Sgt. Skinner is sent out of town on a rail and Tamzarian is officially declared to be the one, true Principal Seymour Skinner.