With this second blockbuster of Summer 2009, the exact opposite thing happened for me than with the first one. Whereas “X-Men Origins: Wolverine” started strong then petered out, J. J. Abrams‘s “Star Trek” reboot is a gigantic bore for more than half its running time, but it eventually grows surprisingly involving once the whole cast is assembled and the plot finally kicks into gear. In that regard, it has a lot in common with “The Matrix Reloaded”, another sci-fi epic that was mostly a dud, but nonetheless delivered solid thrills in the third act.

But let’s got back a little. So this thing opens with a space battle between Romulan war criminal Nero (an unrecognizable, scenery-chewing Eric Bana) and a Federation vessel, and right there I remembered why I was never a fan of previous “Star Trek” movies. Even though everything is cranked up to 11 here, infused with much “Star Wars”-style imagery and an orgy of special effects, it still comes down to shots of impersonal spaceships shooting lasers at each other, intercut with shots of officers yelling orders and crewmembers trading technical mumbo jumbo. Yawn.

We get glimpses of the childhoods of James Tiberius Kirk, acting out idiotically to the sounds of the Beastie Boys’ Sabotage (!?), and of Spock, who must defend himself against Vulcan bullies who bust his balls because he’s half-human. Then we flash forward to them as young adults, and in between dorky expositional dialogue, dorky melodrama and dorky comic relief, I was all but ready to walk out, go home and pop in my “Starship Troopers” DVD, so dying was I for a sci-fi action flick that actually made me feel something like Verhoeven’s funny-smart-badass-gory-sexy masterpiece.

And then it happened. Slowly but surely, as more and more younger versions of the iconic “Star Trek” characters were introduced and each one turned out to be inspired casting, from Zoe Saldana as Uhura to Karl Urban as McCoy, John Cho as Sulu, Anton Yelchin as Chekov and especially Simon Pegg as Scotty, I found myself actually enjoying spending time with these guys. Better yet, events started to accelerate, with Leonard Nimoy as the old Spock popping in through a space-time continuum twist and Zachary Quinto as the young Spock unexpectedly forgetting about logic and letting emotion slip through, as provoked by Kirk (Chris Pine).

From then on, it was all pretty painless for me, if not particularly thrilling. This is still not on the level of “Starship Troopers” (obviously) or even of a “Star Wars” prequel but, again, the 7 leads are all appealing and, against all odds, I ended up feeling like I wouldn’t mind watching them go at it again in the inevitable sequel.