Heading for Parliament, the sector's neutral conference planet, the Enterprise transports peace delegates from two malevolent races, the carnivorous Anticans and the reptilian Selay, both of which want to join the Federation but can't stand each other long enough to occupy neighboring suites. Traveling past a mysterious energy cloud, something curious boards the ship, jumping between machinery and crew members, as if seeking a suitable host and learning about the ship without revealing itself. The crew catches on slowly, as nobody seems seriously affected by the highly intelligent host entity (except Wesley's engineering mentor Singh, killed in a warp technology energy surge).