The entrance of the Sra Keow cave, north of Krabi, Thailand, is dark and quiet. All the local kids who use the pond as a playground are now back home for dinner. The only three people still there, closely watching the motionless pond, trying to see any bubble or glow that could reach the surface now start to worry. The divers were supposed to complete their dive within four and a half hours... Still nothing after six long hours.