The prelude to ZERO HOUR begins at Vanishing Point, home of the Linear Men, where Rip Hunter finds Waverider viewing screens from the now non-existent timeline that, due to his own actions in ARMAGEDDON 2001, was wiped out. The pair argue, Hunter regarding Waverider as dangerous as Monarch, the villain he aimed to stop.
As they argue, their time scopes blank out. Tracking the cause of the problem to Washington in 1994, they discover an anomaly in the timestream. Before they can investigate, they discover that Monarch himself is watching them.
Monarch is aware that Waverider is watching him and takes steps to prevent it happening again, forcing Waverider to track him down which is exactly what he wants.
As Waverider and Hunter head through time to find Monarch, they notice anomalies running through all timelines, something that shouldn’t happen. When they arrive in 1994, they are attacked by Monarch who, when challenged, denies that the anomalies are his doing. Overpowering the two time travellers, Monarch and his captives disappear.
Holding Waverider and Hunter in a stasis field, Monarch is able to leach the ability to travel through time from their technology, sending them bouncing from one era to another. Monarch attempts to force Waverider to help him navigate through time by materialising them in the midst of a war.
He is struck by a stray blast, though, allowing Waverider to escape briefly before Monarch threatens Hunter’s life. Attacking Monarch, Waverider’s energy is siphoned off before he deliberately overloads Monarch’s armour.
This, however, gives Monarch the ability to see into his past and realise that, after he killed his future self in ARMAGEDDON 2001, Dove’s powers merged with his own. This allows him to alter himself and become Extant. Needing only the ability to time travel, Extant steals Waverider’s technology and disappears into the timestream.
Blaming Waverider for Extant’s creation, Hunter attacks him before they realise the futility of their actions, Waverider coming to a dire conclusion.