The 2385 temporal crisis in which the Vau N'Akat leader Asencia attacked the Federation with time weapons and a paradox let the Loom threaten reality.
The Protostar's earlier journey through a wormhole created a time paradox, and by 2385 that paradox threatened the stability of reality itself. The Vau N'Akat leader Asencia used it to strike at the Federation, launching a fleet of ships armed with temporal weapons against every major Federation base.
The USS Voyager and the restored Protostar fought the fleet to buy time, while Wesley Crusher, Rok-Tahk, Zero and the Vulcan cadet Maj'el worked out how to reopen the wormhole to Tars Lamora. Dal, Gwyn and the others beamed down to Solum, where Gwyn defeated Asencia with the support of the other Vau N'Akat. Reopening the wormhole collapsed the time rifts onto Asencia's ships and destroyed them.
The danger was not over, because the Loom, beings from another dimension, swarmed out of the wormhole to consume reality. The crew sent the Protostar through, with Voyager guarding it, and the ship landed on Tars Lamora. That closed the paradox and sent the Loom home. Janeway then led a formal first contact with the Vau N'Akat and retired, and Chakotay took command of Voyager.