In an antique shop, elderly proprietor Jesús Gris discovers a mysterious mechanical device hidden inside an ancient statue. The object, later revealed to be a 16th-century invention, resembles an ornate bug and is filled with clockwork gears and sharp appendages. Upon activating it, Jesús unwittingly unleashes its strange power, which grants him renewed vitality and youth but comes with a horrific price. He becomes increasingly obsessed with the device, experiencing both the marvels of rejuvenation and the terror of its side effects. Meanwhile, a relentless and ruthless industrialist, Dieter de la Guardia, who is terminally ill, learns of the device's resurfacing and is determined to obtain it for himself to gain immortality.

Jesús’s transformation does not go unnoticed, as his granddaughter Aurora grows concerned for his well-being. On the other hand, Dieter enlists the help of his brutish nephew, Ángel, to retrieve the device at any cost, even resorting to violence. As Jesús grapples with the duality of the device's blessings and curses, he must contend with the increasingly aggressive pursuit by Dieter and Ángel. The dark, atmospheric tale intertwines elements of fantasy, horror, and dark humor, exploring themes of mortality, obsession, and the human condition. The journey becomes a race against time and corruption as Jesús seeks to protect his family and make a difficult choice regarding the potent yet dangerous relic.