Supermodel Claudia Schiffer guest stars as Gretchen, a drop-dead gorgeous new lawyer in Greg's office about whom he's having sexual fantasies. Guilt-ridden over his inappropriate thoughtsâ-especially since it's his "four-and-a-half-year anniversary" with Dharmaâ-Greg tries desperately to get Gretchen off his mind, to no avail.

A flower that comes from a reopened "Level Three" of the fertilizer plant brings strange reactions from several people, including Jonathan, Lana, and Pete.

The gang hangs out while waiting for the class picture to be taken.

Keith takes matters into his own hands when he arranges a secret meeting with Carl. Elizabeth realizes who Alexis really is and immediately comes forward. Jack and Mason question her and then convince her to aid in his capture. The safe house is attacked, but Teri and Kim manage to escape. They are then separated by an unforeseen accident.

When Carter is unexpectedly called to a late-night meeting, Charlie's left in charge of entertaining Spencer, a 16-year-old boy whom Carter sponsors through the "Big Brother" program. Having already had a date planned, Charlie has no choice but to bring Spencer along for the ride. Meanwhile, the Mayor is racked with guilt which is causing him insomnia.

Internal Affairs launches an investigation into Terry's death. David begins his own investigation into Vic's actions. Claudette and Dutch investigate the shooting of a churro vendor. The Strike Team busts a gang initiation. Rookie Julien gets pointers from Danny and experiences one of his own initiation rituals as a cop.

Just as Justin is planning to visit Tonya in Chicago, she relapses with her kidney problem. The situation is so bad that Cara rushes her from work to the emergency room. Tonya is in an incredible amount of pain and explains to Cara that this was the reason that she went home the first time. After getting treated she decides she should stay home for the rest of the week, which happens to include the time that Justin will be there. Theo thinks that "Tonya's illness is absolutely realâ?¦she's not faking it. Butâ?¦her not going to work has more to do with sex with her boyfriend".
Meanwhile, Kyle is planning a trip to his father's lakeside cabin. Everyone is planning to go and it seems like couples are forming - Tonya & Justin, Chris & Kurtâ?¦and Keri & Kyle. Kyle is concerned about how this might appear and begs Theo and Aneesa to come up early with him and Keri so it doesn't look like he's going on a "romantic retreat" with her. They initially agree but back out when they realize that they are b

Tonight, Senator John McCain.