Take the Tower

S01E15 Beholder

A sinister hitman employs a laser to blind witnesses to his murders. Fawkes and Hobbes track him down to a blind model who is romantically linked to the killer, but the assassin manages to escape, leaving Fawkes temporarily blinded. When the laser hit him, he was turning invisible, which means he can still see if he covers his eyes with a quicksilver solution. However, this exacerbates his escalating madness. The blind model aids him in coping with his vision loss, and they develop a romantic connection. Fawkes realizes that the killer's latest victim was just bait to draw out his true target at the funeral. Consumed by Quicksilver Madness, Fawkes ultimately hurls the assassin to his demise.