Two brothers, Cole and Andy, trying to survive their encounters with a supernatural monster. they find themselves alive- trapped and completely isolated in a school bus after a mysterious monster attack killed their classmates. The monster is highly sensitive to sound, even the slightest sound will attract it. In order to survive the two brothers must remain silent until they are rescued or until they defeat the monster.At Beginning cole and andy are avoided the monsters, But later cole found that even the heartbeat sounds will attract monsters, they finally understand that only way to survive is to defeat the monster.