Developer Irrational Games launched BioShock Infinite in March. Now, months after selling a $20 season pass for the game’s downloadable content, Irrational is revealing the promised story expansion and a new challenge mode.

The first add-on pack is a $5 challenge pack called Clash in the Clouds. It has 60 challenges for players to compete in and features areas from BioShock Infinite’s story. This add-on is available today for $5 on PlayStation 3 and PC or 400 Microsoft Points on Xbox 360.

Irrational also announced the first story expansion for BioShock Infinite called Burial at Sea, which has players returning to the original BioShock’s underwater-city setting of Rapture. The new campaign stars BioShock Infinite’s Booker DeWitt and Elizabeth in some kind of alternate history.

Burial at Sea is a two-part campaign. It takes place before the events of BioShock. It is “coming soon” for $15.

“We are really excited to offer our fans the content that they have been asking for,” Irrational Games creative director Ken Levine said. “With Clash in the Clouds, people get a pure action experience that takes BioShock Infinite combat to its highest challenge and intensity level. With the Burial at Sea episodes, we are building a Rapture-based narrative experience that is almost entirely built from scratch.”

Both Burial at Sea and Clash in the Clouds are part of the $20 BioShock Infinite season pass. The next episode of Burial at Sea is also a part of that deal.