Lost (2004)

In a tropical jungle, Jack wakes up in agony. He is bruised, bloody and disorientated. A terrible memory flickers across his face. He winces back the pain and begins to run through the trees, reaching a beautiful beach.

He hears sounds - people screaming. He rounds a bend to find the wreckage of a plane crash, surrounded by survivors in shock. His doctor's instincts kick in - and he runs to help those he can, rallying others to his aid.

After treating the injured, the able-bodied survivors rescue what they can from the fuselage, but the cockpit, where the radio transceiver is kept, is missing.

As darkness falls, a monstrous howl rings out from the forest. The tops of the trees shake, but eventually whatever is making the sound goes away, leaving the survivors marooned, exhausted - and now terrified.