Pretty entertaining premise on this week's episode: Dan stole four-year old evidence and planted it at the scene of the crime because he wanted to some action.
That crime ended up beingg that Liz's mom had her car stolen. As you might expect, the old evidence caused a problem because the episode's featured bad guys were under the impression their brother was still alive because his finger prints were on the gun in question.
Through the show's typical twists and turns, Dan and Jack stumbled onto a major weapons case. They also helped Liz's mother recover her car, which got Jack in well with her and teased more flirting between him and his ex.
The weapons dealers were also brought down, though not the man they were planning to sell guns to.