Homes and Watson attend Ascot Races as guests of Lord Coventry. On the first day they lose all their money but, luckily, next morning they are engaged by a new client – an engineer who has had his thumb sliced off by a German chopper. When he describes how something more intimate has been bitten off in a scene of such horror it puts Watson off his breakfast, they go in pursuit of the villains. Meanwhile, at Ascot, Dr. Watson is befriended by The Prince of Wales and given a hot tip by The Jewish Chronicle in the Gold Cup. If the horse wins it will not only recover their losses but also pay the rent arrears at 221B Baker Street.