Paul Brooks, a heavily-bearded man, registers at the Grand Hotel and asks for a room without bath. The man is assigned to No. 12, next to No. 14, occupied by Brant, who had registered earlier in the day. Rooms 12, 14 and 16 really comprise a suite, but have doors which, when locked, allow the rooms to be rented separately. Late that night Jenkins, a diamond buyer in No. 16, is attacked by a masked man, who enters from the next room. The thief is temporarily frustrated and goes back to No. 14. When Francis and Hilton investigate, they find Brant, bound and gagged, in a chair. The man declares he had been overpowered by the burglar. Two hours later, Jenkins is again attacked and this time five big diamonds are taken. The house detectives, investigating, find Brant has disappeared. Out in the hall they meet Brooks, carrying soap and towel, and clad in pajamas, coming from the bath room. The diamond salesman finds something strangely familiar about Brooks and imparts this suspicion to the house detectives. The latter spy upon the man and see him carefully place the soap in his trunk. Overpowering Brooks they examine the soap and find it contains the stolen diamonds. Brooks confesses that he and Brant are one and the same person. After the first attempt to rob Jenkins, he had removed his beard and played Brant. The robbery perpetrated, he retreated to No. 12 and assumed his disguise, donning pajamas and going to the bath room to establish an alibi.