Jack rents a lime green mini van (that barely makes it to the end of the episode.) so that Mac and Bozer can take the team back to their old hometown for the day. Mac gives a presentation at his former school, and afterwards a talented student, Val, is kidnapped in front of Mac and the teacher.
Jack and Mac meet up with Val’s dad, and they suspect he knows more than he’s letting on. Turns out he was running drugs and recently decided to stop. So the drug dealer kidnapped Val in order to encourage him not to seek employment elsewhere.
Jack and Mac work together to rescue Val and stay one step ahead of the bad guys. Mac hides Val in his old treehouse, where she observes the bad guys run off the road by overflowing elephant toothpaste (science!).
Meanwhile, Mac has to face some uncomfortable feelings from the past regarding his Mom’s death and he bonds with Val over the loss of their mothers. Millennial Mac turns into Mentor MacGyver, as he passes his beloved tree house “lab” onto the next generation.