'Harbinger' unfolds the chilling saga of an interstellar object, 'Oumuamua, which is revealed to be more than just a comet—a scout alien spaceship. Its probe, housing a quantum computer, crash-lands in South America and falls into the hands of Christian Becker, a tech billionaire. Utilizing the alien technology, Becker climbs to the pinnacle of wealth and innovation. However, the alien gift proves to be a Pandora's box when things start to spiral out of control. War veteran Will Logan is brought to Becker under suspicion of sabotage, leading to a web of delusion and danger. With his wife, Alex, inexplicably linked to the unfolding drama, Logan finds himself in a vortex where nothing is what it seems.