Going under cover, P.C. Mahoney passes for a gentleman to get into the notorious Moonstone Club. There he meets Clifford Tope, a ne'er do well who is love with cabaret star Cora Mellish. She in turn has run up steep gambling debts and has paid off the Club's blackmailing owner with a stolen necklace. As things heat up Cora seeks help from the easy-going Tope.
| Actor | Role |
|---|---|
 Tom WallsMichael Mahoney | Michael Mahoney |
 Ralph LynnClifford Tope | Clifford Tope |
 Winifred ShotterCora Mellish | Cora Mellish |
 Mary BroughMrs. Decent | Mrs. Decent |
 Robertson HareMiles Tuckett | Miles Tuckett |
 Claude HulbertArchie Slott | Archie Slott |
 Boris RanevskyKosky | Kosky |
 C. V. FranceMicky the Mailer | Micky the Mailer |
 Joan BrierleyMolly Dean | Molly Dean |
 Al BowllySinger(uncredited) | Singer(uncredited) |
| RRoy FoxBandleader(uncredited) | Bandleader(uncredited) |
| HHal GordonTaxi Driver(uncredited) | Taxi Driver(uncredited) |
 Kay HammondMimi-Cocktail Shaker(uncredited) | Mimi-Cocktail Shaker(uncredited) |
| EEileen MunroMinor Role(uncredited) | Minor Role(uncredited) |
 Reginald PurdellWaiter(uncredited) | Waiter(uncredited) |
 Lew StonePianist(uncredited) | Pianist(uncredited) |
 Norma VardenMrs. Tuckett(uncredited) | Mrs. Tuckett(uncredited) |