With San Francisco transit workers threatening to strike, Judge Nicastro enlists Kate's help mediating between the two embattled sides: the up-in-arms transit workers and their allegedly bankrupt employer, Bay City Metro. As Kate soon learns, the conflict has the potential to bring down not just the city's transportation system, but the career of her friend Judge Nicastro, who apparently has a long and unpleasant history with hotheaded union leader Charlie McKay. To resolve the dispute, Kate will have to find a way to appease the disgruntled union workers and get to the truth about Bay City Metro's finances, all while also trying to keep Judge Nicastro from losing his job over the case.
While Kate struggles to keep the trolleys running (and Judge Nicastro out of jail), Leo does his best to stay out of Kate's personal life, which is getting increasingly complicated in the wake of Kate and Ben's recent kiss. Despite Ben's attempts to pursue something more, Kate's difficult case-and more importantly, her doubts-may be holding her back from taking their fledgling romance any further.