A lone astronomer spies a massive object in space hurtling towards earth at a pace defying the laws of known physics. When word finally gets out to the public, an unrivaled panic clenches the world's leaders - and global chaos unfolds. When Halcyon finally arrives, and it doesn't act as predicted, military, civilian and scientific leaders aboard the International Space Station are left to try and make sense of the aftermath, and the unexplained events unfolding in Halcyon's wake.
