Enlarge By Richard Foreman, Warner Bros. Pictures Straight shooter: Christian Bale continues the saga of John Connor, the human Resistance leader in a post-apocalyptic world, in franchise's fourth installment.  WATCH THE TRAILER

But without Arnold front and center, the heavy-metal fracas is just not much fun. Christian Bale stars in this lackluster fourth installment in the Terminator series, but his Batman-Terminator crossover doesn't work. Things do explode well, and loudly. The machines are bigger, shinier and meaner than ever, and the world they inhabit is even more grim and bleak. But the dramatic elements flat-line; any kind of humanity is in short supply.

Bale is surprisingly one-dimensional as John Connor, the leader of the human Resistance movement whose destiny is linked to the future of mankind in this doomsday action franchise. He seems to be simply recycling his gravelly Dark Knight growl.

Newcomers to the series Sam Worthington and Anton Yelchin come off better than Bale in this post-apocalyptic adventure. Worthington plays Marcus Wright, whose last memory was his impending execution in 2003. He appears in the war-torn landscape of 2018, unaware how he got there. Just before dying, he agreed to donate his body to science, urged on by Dr. Kogen (Helena Bonham Carter). Her research gets usurped by the evil artificial-intelligence conglomerate, Skynet.

As the Resistance leader, Connor must decide whether to trust Marcus. Meanwhile, Skynet has captured Kyle Reese (Yelchin), a Resistance fighter key to the entire saga, and Reese's young cohort, Star (Jadagrace Berry). Yelchin (Star Trek's Chekhov) seems to be the go-to guy for summer blockbusters. He has some of the best lines, such as his directive after encountering Marcus: "Come with me if you want to live." Worthington has a quiet intensity marred only by yelling "Nooooo!" three times in about 10 minutes.

Director McG (both Charlie's Angels movies) is all about visuals and creating an ominous sense of disorientation, but he's not as deft with storytelling or eliciting performances. Few characters ever say more than a couple of sentences at a time, and when they do, it's often to assert the obvious. The predictable story feels as if it were written by a computer program labeled "sequel." (Rated PG-13 for intense sequences of sci-fi violence and action, and language. Running time: 1 hour, 55 minutes. Opens Wednesday night in some markets, nationwide on Thursday.)