The first half of BioShock Infinite’s first piece of downloadable content is completely combat-free, says Irrational Games creative director Ken Levine.

Speaking with IGN, Levine said that was one of the things he was looking forward to the most about the expansion.

“It’s just playing in that world, you know, the Rapture you’d never really seen before, and watching Booker and Elizabeth use their wits to solve a problem and just soak in the atmosphere,” he said.

Burial at Sea takes place in Rapture, the world of the original BioShock, but before that city's calamitous fall.

Its story begins on New Year's Eve in 1958, the night when war broke out in the city – a year prior to the events of the first BioShock.

Although the content is built on BioShock Infinite’s existing systems, some gameplay features won’t be translated from Columbia to the underwater city, said lead animator Shawn Robertson.

“We definitely have some systems from Columbia that we bring over to Rapture, but really Rapture is its own place,” said Robertson.

“We don’t want to try to shoehorn technology from Columbia into Rapture just because we have it.”

Despite the change of setting, Burial at Sea was still the story of Booker and Elizabeth, added level designer Amanda Jeffrey.

“For BioShock one, Rapture was the main character,” said Jeffrey.

“For Infinite, I will say that Elizabeth is the main character. Now we have our two leading ladies playing opposite each other, and we get to see how both react to the other.”

Elizabeth has progressed as a character, added Jeffrey.

“She’s not wide-eyed and bushy-tailed, fresh-out-of-the-tower Liz,” she said.

“She’s different this time around, but some of their interactions definitely will feel familiar to those who have gone through Infinite.”

Burial at Sea does not yet have a release date, however all BioShock Infinite’s Season Pass downloadable content is due to arrive before April 2014.