Highly successful construction engineer Howard Gentry calls on Checkmate after an apparent attempt on his life. Checkmate suspects his identical twin brother Robert, but Howard does everything he can to dissuade them of that suspicion. His reasons for doing so lead to an intriguing conclusion.
| Name | Type | Role | |
|---|---|---|---|
| Lewis Reed | Writer | ||
| Sheila Bromley | Guest Star | ||
| Stephanie Hill | Guest Star | ||
| Audrey Dalton | Guest Star | ||
| Jeane Wood | Guest Star | ||
| Paul Langton | Guest Star | ||
| Lloyd Bridges | Guest Star | ||
| Barney Phillips | Guest Star | ||
| Paul Stewart | Director |