Walt finds out that Judge Creary, who they are trying to get recused from presiding over their case, went off the wagon. He had been attending AA. When he does drink he tends to have relapses. That helps Walt have a different judge assigned to the case of a woman who allegedly hired her lover to off her husband.
Another part of the plot line was Grace's acting out. A girl in her class dies of an overdose. Supposedly it was over a guy who is a bad boy. Grace hooks up with him and starts missing school. That's caught on video by Peter's opposition. Eli reads Alicia the riot act that it's impossible to factor out the kids in the campaign for governor. Meanwhile Zack has been fundraising for Peter, under an assumed name. He's quite good at it.
There's more tedious activity about Kalinda and Nick but I will spare you that.