When a building under construction collapses, Cal and Gillian must determine if someone on the scene might have sabotaged it and how. The safety of workers still trapped inside could depend on it. Meanwhile, an Internet entrepreneur planning to propose to his girlfriend wants to know if she really loves him or if she's after his money.

An undercover cop chasing a drug suspect mistakenly shoots an innocent teen, and Cal is hired to determine the man's intentions. Meanwhile, Loker's lie during a recent Ponzi-scheme investigation could come back to haunt him (and Torres as well) when Cal tells them that they'll be deposed in a lawsuit over the matter; and Cal's suspicions that Foster's husband is having an affair are raised anew when he sees him again with the woman he had seen her with before.