Addison's brother moves to LA and begins working at the rival practice, setting the stage for a crossover event with Grey's Anatomy. Archer (a neurologist) is in town and she's treating a pregnant woman who is having a stroke. The parents are getting a divorce and the woman wishes she wasn't pregnant because the baby is keeping her soon-to-be ex-husband in her life.

Archer wants to treat the woman's brain and save both but Addison isn't convinced his way is what is best for the baby.

They put her into surgery to save the woman, which they do, but they have to deliver the baby early.

Addison is also mad about Archer going to work for Charlotte, a practice that is trying to submarine her, and with Archer being there to butt into her life. She wants him out of her city.

She finally comes to grips with his being there but warns him to stay out of her personal life.

Violet still won't tell the boys that either one of them might be her baby's father. Sheldon senses that there is something up with her but he doesn't know what.

She spends all episode getting anti-children comments from both men.

Violet also meets with the 52 year-old embryo seeker about her daughter's problems with her. The mother realizes that she wasn't a good mother the first time around and wants another chance because she can't bring her daughter back.

Violet changes her mind and thinks they should implant Sharon with the embryos.

Naomi turns to Sam for advice about Addison catching her sigh Archer. She's also treating a woman, Sharon, whose daughter got in-vitro and was subsequently killed in a car accident (along with her husband).

Sharon wants her daughter's leftover frozen embryos. To be transplanted into her own uterus. At the age of 52. Oh my goodness.

Violet informs Naomi that the dead girl hated her mother and would never agree with giving her mother another child.

After a night of sex, Archer informs Naomi he can't hang out the next night because he has a date. She pulls away (as well she should) and he calls himself "the good-time guy."

She calls Sam for advice, which is very cute, and at the same time, his girlfriend Sonja is there getting undressed for sex.

Naomi then turns to Addison for advice. Addison tries to warn her off and voices her frustrations about Archer messing in her life.

Pete is treating a guy named Keith who is a drug user with Hep C.

He comes to Pete for clean needles. Keith goes a little crazy, smashing shelves and knocking Dell down.

Dell's view of the world has him arguing that Keith needs to go to prison. Pete thinks Keith can get clean with the right help.

Pete goes to see Keith's wife, who cannot believe Pete is enabling him with clean needles. In our big moral dilemma of the week, Pete calls addiction a disease and the wife calls it a choice.

Pete finds Keith in the hospital after being found passed out on the beach. He has an infection from not using the clean needles and Pete tries to yell some sense into him about saving himself.

He gets Violet to sign a form that forces him into a psych facility for 72 hours, with the hope of a 30-day hold.

Keith resists but the cops lock him up in the psych ward.

Charlotte is mad and barely speaking to Cooper because she thinks he turned down her proposal, which he did not do.

Turns out she's not mad, she's humiliated and hurt.

Cooper finally insists on proclaiming his love for her and telling her that he won't give up even if she has.

Charlotte finally starts speaking to him again and brings a casserole as a peace offering. She tells him that moving in is a good first step.

Unfortunately, he just decided to move in with Violet.

Sam is having anxiety-induced asthma and can't seal the deal with Sonja. Naomi helps him get some stuff from Pete for his asthma.