What Lies Tangled, Pt. 1

S9, E5: When an idyllic Oxford summer's day is shattered by a parcel bomb, Lewis and Hathaway are called in to investigate. The victim of the attack is eminent mathematician Adam Capstone, a genius in the field of Knot Theory. Adam was notorious for his numerous affairs with attractive young students, so could his wife have the motive to want him dead?