Álex de la Iglesia	...	(Director)
Jorge Guerricaechevarría, Álex de la Iglesia	...	(Writer)
Javier Gutiérrez	...	Juan
Leonor Watling	...	Sonia
Sancho Gracia	...	Domingo
María Asquerino	...	Anciana 1
Antonio Dechent	...	Fernández
Terele Pávez	...	Mujer de Domingo
Ramón Barea	...	Marcos
Eulalia Ramón	...	Teresa
Asunción Balaguer	...	Anciana 2
Manuel Tallafé	...	García
Cesáreo Estébanez	...	Martí
Gracia Olayo	...	Enfermera
Enrique Martínez	...	Eslavo
Penélope Velasco	...	Dependienta
Antonio de la Torre	...	Operario
José Luis Moreno	...	Cinematographer

Summary: Juan with his wife Sonia and their daughter move into their new house and slowly begin to discover that they might not be alone. They hear voices over the baby monitor, and Juan begins to become more and more obsessed with the idea that they aren't alone in the house. He buys a video monitor so they can keep an eye on their baby, and one night he sees a figure on the screen, looking over their child's cot.