The year 2015 is starting to wind down, and what that means for "Attack on Titan" fans is that the second season of the show is inching closer and closer.

According to Moviepilot, the second season of the popular anime is set to premiere by spring of next year, although there's still a bit of uncertainty regarding what it will actually be about.

This is mainly because there's not a lot of source material for the show to work with at this point.

According to the Latino Post, there are currently only two story arcs available in the manga that can reasonably be used for the show as of now, and that could present director Tetsurō Araki with a bit of a dilemma. He can either wait for the manga to produce more story arcs that can be used for the series or he could also decide to go in a different direction from the source material and engineer other storylines.

There's no indication as of yet that Araki is leaning towards either direction, and with the second season not set to premiere until the spring, there is hope that the manga can catch up enough to provide the material that will be needed.

As for what else fans can expect from the second season of "Attack on Titan," footage leaked earlier this month revealed some small details about the show.

According to Geek Snack, one of the most important tidbits revealed in the leaked footage is that there appears to be a titan trapped inside the wall that surrounds the city.

Hanji Zoe is the one to find out about this mysterious detail and after she confronts Pastor Nick about it, she begins to wonder if there may be more than just one titan that has been lying dormant inside those walls.

Unfortunately, fans will have to wait until the debut of the second season of "Attack on Titan" to find that out.