Saw

“How much blood would you shed to stay alive?”

Dr. Lawrence Gordon (Cary Elwes) wakes chained in a filthy bathroom across from Adam Radford (Leigh Whannell), a stranger he has never met. Between them lies a corpse and a tape recorder explaining their only way out: one of them has to die. James Wan traps both men in concrete walls while a serial killer's logic closes around them, and what matters most becomes not escape, but whether they can trust each other enough to survive it.