Thorne realizes that both Makepeace's mistress Stella Tyson and his wife Isobel could be lying about his marriage proposal to Stella and of the break in to his flat, but both are on the defensive. However, it also means that Makepeace's flask could've been poisoned earlier than thought. Carl Sillmans celebrate following Maitland's work in discrediting Fane and Browning and throw a party. Maitland brings Kate, much to Field's chagrin, but are salutations a little premature with Makepeace's killer still at large and Thorne ready to make his move?