Marauding mobs of huge Humboldt squid are spreading northward along the Pacific coastline, devouring salmon stocks already diminished by other threats. A team of scientists and divers have a disturbing theory, which if proven true, could mean the end of West Coast salmon altogether. To investigate the mystery, the team heads to ground zero, the Sea of Cortez, where they'll suit up in stainless steel chain mail and jump into squid-infested waters to perform new field tests.