The clock tower is found on the left side of the balcony above the tavern. Jack’s compass is required to find the key on the left. Place the key on the crank and turn it to raise the green bars along the side of the clock tower. Choose a female character and jump to the green bar. Swing and jump up to the next set of green bars and finally to a 3rd one where you will be able to pull yourself on a platform. This will unlock the “The Green Flash” trophy.