Highlights from the Fourth Episode of Season 2

When the CEO of a financial consulting company is poisoned to death, Holmes and Watson are called upon to track down the killer.

Sherlock

1. Sherlock

A woman from Sherlock’s (Jonny Lee Miller) past emerges as a possible suspect when the CEO of a financial consulting company is poisoned to death. Photo: Patrick Harbron /CBS ©2013 CBS Broadcasting, Inc. All Rights Reserved
Sherlock

2. Sherlock

A woman from Sherlock’s (Jonny Lee Miller) past emerges as a possible suspect when the CEO of a financial consulting company is poisoned to death. Photo: Patrick Harbron /CBS ©2013 CBS Broadcasting, Inc. All Rights Reserved
Holmes, Watson and Gregson

3. Holmes, Watson and Gregson

Holmes (Jonny Lee Miller, left), Watson (Lucy Liu, middle) and Gregson (Aidan Quinn, right) are called upon to track down the person who poisoned the CEO of a financial consulting company. Photo: Patrick Harbron /CBS ©2013 CBS Broadcasting, Inc. All Rights Reserved
Captain Gregson

4. Captain Gregson

Gregson (Aidan Quinn) must track down the person responsible for poisoning the CEO of a financial consulting company. Photo: Patrick Harbron /CBS ©2013 CBS Broadcasting, Inc. All Rights Reserved
Holmes

5. Holmes

Holmes (Jonny Lee Miller) is called upon to track down the person who poisoned the CEO of a financial consulting company. Photo: Patrick Harbron /CBS ©2013 CBS Broadcasting, Inc. All Rights Reserved
Holmes

6. Holmes

Holmes (Jonny Lee Miller) is called upon to track down the person who poisoned the CEO of a financial consulting company. Photo: Patrick Harbron /CBS ©2013 CBS Broadcasting, Inc. All Rights Reserved
Gregson

7. Gregson

Gregson (Aidan Quinn) must track down the person responsible for poisoning the CEO of a financial consulting company. Photo: Patrick Harbron /CBS ©2013 CBS Broadcasting, Inc. All Rights Reserved
Holmes and Watson

8. Holmes and Watson

Holmes (Jonny Lee Miller, left) and Watson (Lucy Liu, right) are called upon to track down the person who poisoned the CEO of a financial consulting company. Photo: Patrick Harbron /CBS ©2013 CBS Broadcasting, Inc. All Rights Reserved
Sherlock

9. Sherlock

A woman from Sherlock’s (Jonny Lee Miller) past emerges as a possible suspect when the CEO of a financial consulting company is poisoned to death. Photo: Patrick Harbron /CBS ©2013 CBS Broadcasting, Inc. All Rights Reserved
Sherlock

10. Sherlock

Sherlock (Jonny Lee Miller) encounters a woman from his past while investigating a murder. Photo: Mark Schafer /CBS ©2013 CBS Broadcasting, Inc. All Rights Reserved
Sherlock encounters an old friend

11. Sherlock encounters an old friend

Sherlock (Jonny Lee Miller, right) encounters Anne Barker (Laura Benanti, left), a woman from his past, while investigating a murder. Photo: Mark Schafer /CBS ©2013 CBS Broadcasting, Inc. All Rights Reserved
Sherlock

12. Sherlock

Sherlock (Jonny Lee Miller) encounters a woman from his past while investigating a murder. Photo: Mark Schafer /CBS ©2013 CBS Broadcasting, Inc. All Rights Reserved
Sherlock

13. Sherlock

Sherlock (Jonny Lee Miller) encounters a woman from his past while investigating a murder. Photo: Mark Schafer /CBS ©2013 CBS Broadcasting, Inc. All Rights Reserved
Sherlock encounters someone from his past

14. Sherlock encounters someone from his past

A woman from Sherlock’s (Jonny Lee Miller) past emerges as a possible suspect when the CEO of a financial consulting company is poisoned to death. Photo: Mark Schafer /CBS ©2013 CBS Broadcasting, Inc. All Rights Reserved
Sherlock

15. Sherlock

A woman from Sherlock’s (Jonny Lee Miller) past emerges as a possible suspect when the CEO of a financial consulting company is poisoned to death. Photo: Mark Schafer /CBS ©2013 CBS Broadcasting, Inc. All Rights Reserved
Laura Benanti as Anne Barker

16. Laura Benanti as Anne Barker

Sherlock (Jonny Lee Miller, left) encounters Anne Barker (Laura Benanti, right), a woman from his past, while investigating a murder. Photo: Mark Schafer /CBS ©2013 CBS Broadcasting, Inc. All Rights Reserved
Sherlock encounters a woman from his past

17. Sherlock encounters a woman from his past

Sherlock (Jonny Lee Miller, left) encounters Anne Barker (Laura Benanti, right), a woman from his past, while investigating a murder. Photo: Mark Schafer /CBS ©2013 CBS Broadcasting, Inc. All Rights Reserved
Watson

18. Watson

Watson (Lucy Liu) is called upon to track down the person who poisoned the CEO of a financial consulting company. Photo: Patrick Harbron /CBS ©2013 CBS Broadcasting, Inc. All Rights Reserved