'The Good Wife' Season 5 Episode 18 Spoilers: Michael J. Fox's Louis Canning Joins Lockhart/Gardner [Video]

Diane made a bold proposal on the latest episode of "The Good Wife."

In "Material World," the team attend Will's (Josh Charles) funeral. Afterwards, Diane (Christine Baranski) and Alicia (Julianna Margulies) spend time drinking together and reminiscing about the good times.

At one point, Diane drunkenly suggests that their two firms merge.

Damian, the man who was stealing clients from Will, happens to overhear their conversation, and tells David Lee about the potential merger. 

Back at Florrick/Agos, the father of the man who shot Will wants to fire a wrongful prosecution suit, but Alicia says she'll quit the firm if they take on the case.

Meanwhile, Kalinda (Archie Panjabi) and Cary (Matt Czuchry) are still lovers, but Kalinda is also sleeping with her police officer girlfriend simultaneously.

Later, the two firms go to court against each other on opposing sides of a divorce case. The couple cheated on each other, and neither spouse can take the moral high ground.

Alicia breaks down outside the courtroom, and goes home and crashes. Finn shows up at Alicia's house because she missed a meeting, and finds that she's still in bed. He's tries talking to her, and offers his help.

Peter (Chris Noth) argues with her about Will's death. Alicia tells Peter that she won't divorce him, because they are both valuable to each other. Instead, she tells him it will be a "business arrangement" from now on, not a marriage. She says he can sleep with whomever he likes.

In the end, the divorce case concludes with Diane overruling David Lee.

David Lee then calls Michael J. Fox's character, Louis Canning, and asks him if he's interested in a merger.

On the next episode, "All Tapped Out," "Florrick/Agos represents an NSA whistle-blower and learns that the agency has been monitoring the firm and Alicia's personal life. Meanwhile, Louis Canning joins Lockhart/Gardner; and Alicia goes after the State's Attorney when he tries to make Finn a scapegoat in the Jeffrey Grant case."

TVLine also spoke to series cocreators Robert and Michelle King, who explained why Michael Cerveris is playing the state attorney instead of John Leguizamo, who was originally cast in the role.

"We were so honored to get John Leguizamo for The Good Wife, but felt we were not utilizing him in the best way possible as James Castro," they explained. "We are hoping to work with him again in different role, as he is such a splendid and collaborative actor."

Watch the promo below for "All Tapped Out," which airs Sunday, April 20 at 9 p.m. on CBS.