The forces of Heaven and Hell are at constant war here on earth, but only a 'gifted' few are able to see what's going on. One such person is John Constantine (Keanu Reeves), who uses his gift to send the unruly demons back down to hell if they step out of line and try to affect the balance too much.
Dying from cancer, Constantine believes he'll be going for hell for committing the sin of attempted suicide years earlier, and so his exorcisms are an attempt to buy his way back into Heaven.
But when the twin sister of LA cop Angela Dodson (Rachael Weisz) dies under mysterious circumstances, he finds himself being dragged into helping her investigation as she's convinced that her death is anything but a simple suicide and that other forces are at work.
As they look into things, Rachael finds herself being taken deeper into the surreal world that exists behind the veil of our reality, where demons, angels and half-breeds walk amongst us and an all new battle between heaven and hell threatens to engulf everything.
Based on the "Hellblazer" comic book series by DC Comics, whilst the characters and performances are solid enough, the plot isn't really that engrossing and relies too heavily on CGI animation. This is an entertaining enough popcorn flick, although doesn't quite make the grade in terms of cinematic excellence.