"World War Z" — Might there be a real zombie apocalypse one day? The way zombies have invaded our pop culture the last several years, it's maybe a bit less implausible than it once was. What IS increasingly quite plausible, alas, is a global pandemic, and "World War Z," the long-awaited Brad Pitt thriller, cleverly melds that real-life threat into the more fanciful zombie premise. Talk about more bang for your buck: Once you've settled back into your seat after a good snarling zombie chase, there's nothing like the thought of a SARS outbreak to get the blood racing again. Despite the much-discussed production delays and budget overruns, this movie, based on the 2006 novel by Max Brooks (son of Mel), is pretty much what you'd want in a summer blockbuster: scary but not-too-gross zombies, a journey to exotic locales, a few excellent action scenes, and did we mention Pitt? As Gerry Lane, a former U.N. investigator called upon to save the planet, Pitt is a calm, intelligent presence amid the insanity. The most impressive scene is at the beginning, as the streets of Philadelphia are suddenly overrun by packs of wild, raging zombies. For an hour, the action is swift: North Korea, Israel, a harrowing plane crash. The final act takes place on a dramatically smaller scale, and at a slower pace. Oh, a reminder: Turn off those cellphones. After all, it's not just your movie-going partner you'll annoy here. Cellphones also happen to awaken zombies. Consider yourself warned. PG-13 for intense frightening zombie sequences, violence and disturbing images. 116 minutes. Three stars out of four.