13. An Enemy of Fate

Complete story — includes the ending

Learning the Observers and Loyalists are on to Broyles, the team step up their plans. Peter learns that someone will have to travel with the mute Michael to talk to the scientists who fathered the Observer technology, and Walter already planned to sacrifice himself. Later, September decides to take Walter's place. December is found dead in his apartment, since the Observers were on to him. As a backup plan, they have to intercept a wormhole shipment near the Observer headquarters, which would be guarded by Loyalists. Peter and Olivia unleash various biohazards (from past Fringe events as seen in the episodes " The Cure ", " The Dreamscape ", " Ability ", " Snakehead ", and " Os ") into the building's ventilation, while also rescuing a captured Broyles. During a firefight to keep the Loyalists and Observers at bay, the resistance activate the wormhole to 2167. Windmark attempts to stop them, only to be crushed by two trucks before he could teleport out, caused by Olivia using her Cortexiphan powers. As September runs with Michael to the wormhole, September is shot and dies, leaving Walter to take the child. As a result of this, the timeline has been rewritten, where back in 2015, the Observer invasion never occurred. In the final scene, Peter opens an envelope addressed from his father, which contains only a piece of paper with a drawn white tulip on it.