The tale of two skilled professionals--one a cop, the other a criminal--who aren't as different as they think. Vincent Hanna is an intense cop on the trail of ruthless armed robber Patrick McLaren. After a botched heist, the two men confront each via a full scale battle on the seedy streets of Los Angeles.

An experimental submarine with a very experienced crew, the "Siren II" is sent to find out what happened to the "Siren I" after it mysteriously disappeared in a submarine rift. Things go awry when they begin to find things that shouldn't be there...