The second season of Marvel's Agents of SHIELD hits US screens on September 23rd, and we're very excited about that fact. The first season took some flack early into its run and it wasn't until around mid-way through its run before it really picked up steam, thanks in no small part to Captain America: The Winter Soldiers major contributions to its plot. After it was revealed that Hydra secretly controlled SHIELD, things kicked off in a major way for Agent Coulson and his mish-mashed team - and we loved it. Now the series is coming back for a second round, and we sincerely hope that the writers haven't dropped the momentum they picked up last time around. From the looks of the recent casting announcements it looks like we're not going to be disappointed. Not only are Lucy Lawless and Joss Whedon regular Reed Diamond taking on major supporting roles as good and bad guys respectively, but the legendary Kyle MacLachlan is set to appear as Skye's father and the show is even upping its game in terms of the villain presence with the news that Crusher Creel aka The Absorbing man will be causing havoc for Coulson and his homies. That's a lot to get excited for, and that was before Marvel even released the first proper-length teaser for the season online. The video's full of tantalising snippets that show just how much has changed for the characters since the beginning of the first season but also raises countless questions about the direction the story's going to take this year. Take a look at the teaser below and then join us as we delve into the ten biggest questions raised about the future of Agents of SHIELD.