It is 2033 - and the world has changed forever. The first alien radio transmission has been received on Earth. The signals are impossibly complex, a torrent of encrypted information that no computer - and certainly no human - can crack. The decision to reply is made and messages of goodwill are beamed into space. Humanity waits for an answer.

Thirty years later, the signals suddenly dry up. And then scientists detect a huge space Cloud, immense in size, immeasurable in power, hurtling towards the Earth. And so, as one man desperately struggles to decode the initial alien transmissions, a united Earth prepares to launch a nuclear strike against a seemingly unstoppable foe.

But when the first part of the alien code is broken, humanity realises with a growing dread that the enemy may be closer than they knew.