The Tholians make their move: Siroc tests a new weapon against Starfleet, while the largest meeting of Alpha Quadrant powers since the Dominion War is not going so well. They know they need to band together against the Tholians but the Federation is keeping secrets from its allies. The illegally joined Trill, Zen, has difficulty with his symbiont while the first-ever portrayed Tellarite Captain faces down the Tholians' deadly weapon.