Ep 16. The Mistress Always Spanks Twice

Castle (2009) season 2 episode 16, titled "The Mistress Always Spanks Twice", follows the story of a dominatrix who finds herself at the center of a murder investigation.

The episode begins with Castle and Beckett investigating the murder of a man who was found dead in a hotel room. The man appears to have been involved in a BDSM relationship, and there are several clues that suggest his death may have been related to his sexual preferences.

As the investigation progresses, the detectives meet several individuals who were involved with the victim, including his wife and his mistress. The mistress, a dominatrix named Lady Irena, becomes a key suspect in the case when it is discovered that she had a motive and opportunity to commit the crime.

However, Castle is convinced that Lady Irena is innocent and decides to take matters into his own hands. He goes undercover as a client of Lady Irena's in order to get close to her and see if there is any evidence to suggest she is the killer.

As Castle spends time with Lady Irena, he begins to unravel a complicated web of deceit and betrayal. He discovers that the victim was not the man he appeared to be, and that Lady Irena may have been involved in a plot to take down an international criminal organization.

As the case comes to a close, Castle and Beckett find themselves in a race against time to catch the killer before they can strike again. With the help of Castle's insights and Lady Irena's knowledge of the criminal underworld, the detectives finally solve the case and bring the culprit to justice.

Overall, "The Mistress Always Spanks Twice" is a thrilling and suspenseful episode of Castle that explores the darker side of human sexuality and the lengths people will go to protect their secrets. It is a must-see for fans of the show and anyone who enjoys a good mystery.