For William Moseley, watching "The Chronicles of Narnia: Prince Caspian" was somewhat nerve-wracking. Not just because his role of Peter is more at the center of this film than 2006's blockbuster "The Lion, the Witch and the Wardrobe," but also because it would be his last chance to live in C.S. Lewis' magical world. Still, he says all he could think of was, "How lucky did I get to get that part?"

Moseley's on-screen sister, Anna Popplewell, is also taking her leave of the franchise, and, while she calls it "bittersweet," she's more than ready to move on.

"I had my first audition for this when I was 13 and I'm 19 now, so I haven't been doing 'Narnia' for six years nonstop, but it's been a big chunk of my life," Popplewell says. "I don't want to play the same character seven times. I think people would get bored of it and I don't know if I could spend seven times seven months doing it."

While Lewis may have removed the younger versions of Peter and Susan from the remaining five books (their siblings Lucy and Edmund appear again in numerous installments), he left the groundwork for director Andrew Adamson to provide both actors with compelling story lines in "Caspian." After returning to Narnia 1,300 years after they left it (only a year in "real" time), they find the kingdom a much darker place. Peter has to deal with the frustration of a potential rival in Caspian, and Susan is introspective about whether Narnia is really where she belongs (oh, and she finally gets to really show off her prowess with that bow and arrow). Moseley admits his on-screen responsibilities were much more difficult this time around.

"In the first one, I really essentially played myself. The older brother trying to do selfless things," Moseley says. "Now, Peter is much more angry, much more frustrated, headstrong and self-entitled. And I really had to get in touch with all those angry emotions and take them out on my fellow little siblings, which wasn't easy at times."

Predictably, saying goodbye on the set wasn't all that fun either. Moseley's last day had him in the middle of a battle scene, leading all the other Narnians in a charge against the evil Telmarines. He recalls it as a "very emotional moment."

"It was this beautiful sunset in the Czech Republic and we were all running, the whole cast, down this hill and it just felt like we were bound for this very, very last moment," Moseley said. "And it sort of immortalized our experience together. It sort of embodied everything we've been through."

Still, both actors admit there is some solace knowing the strong connections they formed with younger co-stars Georgie Henley (Lucy) and Skandar Keynes (Edmund) may lead to lasting friendships.

"I think when people send kids on summer camps or bonding trips they send them to do high rope climbing and extraordinary things," Popplewell says. "And when you do extraordinary things with people, like fighting battles or simulating huge wars, you do bond very quickly."

Matter of factly, she adds, "We stayed friends between the movies. I don't see any reason why it would stop now."

"Prince Caspian" opens nationwide May 16.

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