The Coronet Hotel is one of Fifth Avenue's finest, but like any other building, it can harbor trouble and unhappiness, and in the elegant suite of the Cunningham sisters, Lois, the younger sister, is sitting weeping and crying out angrily to her sister, Helene. She wants to go out and enjoy herself, but her sister is refusing to let her, as she believes she will be playing cards for money. Helene has looked after Lois since their parents died, and she intends to continue doing so until Lois is married to Edgar. They continue to squabble until the doorbell rings and Helene opens the door, greeting them warmly. But then two shots ring out clearly, and Helene is gunned down right there in the doorway! The shooter runs away down the stairs, and Lois never sees their face, so it's down to Mr Chameleon to solve the case...