: This is the most dangerous rule, as the intensity of love is too much for his mechanical heart to bear. Key Characters and Plot

To keep his mechanical heart ticking, Jack must follow three strict rules:

: Strong negative emotions can overload the delicate gears.

Jack y la mecánica del corazón (The Boy with the Cuckoo-Clock Heart) is a poetic, bittersweet story by Mathias Malzieu that blends fantasy and reality. Set in late 19th-century Edinburgh, it follows Jack, a boy born on the coldest day in history with a frozen heart. To save him, the midwife Madeleine replaces his heart with a wooden cuckoo clock. The Three Sacred Rules

: Messing with the mechanism could be fatal.