As Tulkinghorn edges closer to the truth, Lady Dedlock puts her reputation at risk when she pays an undercover visit to Nemo's former haunts. John Jarndyce finds himself increasingly attracted to Esther, but Richard makes an announcement which causes him dismay. And Woodcourt has news that comes as a terrible blow to Esther.

Richard's inability to settle causes a rift with John Jarndyce, much to Ada's dismay. Tulkinghorn finally unearths the possible identity of the mysterious Nemo. Nemo's old friend Sergeant George has the evidence he needs to prove it and Tulkinghorn will stop at nothing to force George to hand it over. But George has even more problems when Gridley turns up on his doorstep, on the run from the law and infected with the fever.

Tulkinghorn believes Lady Dedlock is in his power, but she continues to defy him. George's anger knows no bounds when Tulkinghorn breaks his promise and leaves him in financial ruin. And a marriage proposal surprises Esther - but is it from the right man?

Esther's feelings for Woodcourt grow stronger despite her best intentions. Inspector Bucket begins his murder investigation with no shortage of suspects. An early arrest appears to wrap the case up quickly, but a spate of poison pen letters suggests that all is not as it seems.

Richard and Ada's news causes great concern for Esther and Jarndyce. Inspector Bucket's investigation gathers steam when he tracks down the mysterious letter writer. As evidence mounts against Lady Dedlock, Bucket sets a trap for the killer - with astonishing results.