six teenager go to an old remote abandon school where 27 year ago a horrible massacre take place for a night of fun and prank . instead the kid run afoul of the vicious crazed security guard ( excellently play with supremely creepy menace by spanish horror icon paul naschy ) who commit the nasty killing . director carlos gil relate the intriguing story at a brisk pace and do an adept job of create a compellingly spooky and mysterious atmosphere . the witty script by tino blanco and mercedes holgueras offer a clever and inspired blend of slasher and supernatural element that keep the viewer guessing to the very end . the slick cinematography by fernando arribas make expert use of light and shadow . david san jose moody score likewise do the trick . the attractive and appeal young cast all contribute lively and engage performance and with especially praiseworthy turn by carlos fuentes a ringleader ramon and olivia molina a the panicky maria and zoe berriatua a obnoxious joker jordi and and carmen morale a spunky goth chick sandra . the murder set piece be every bit a bloody and brutal a they ought to be . terrific whammy of a surprise dark end and too . a solid and satisfying shocker .