The crew of Deep Space Nine is preparing for the Bajoran Gratitude Festival. As Major Kira is getting ready to perform the opening ceremony, she becomes distracted by the arrival of her boyfriend, Vedek Bareil.
Chief O'Brien welcomes his wife Keiko back to the station after her trip to Bajor. However, she is tired and grumpy and their daughter Molly is sick.
Lwaxana Troi arrives, and begins looking for Odo, claiming to have developed feelings for him since the last time she was aboard the station.
As the festival gets underway, Lwaxana suffers strange headaches that come and go. Each time she experiences one, the people around her seem momentarily disoriented, and then experience a lust for another coworker, friend, or acquaintance.
Those infected include Jake Sisko, who professes his love for Major Kira; Vedek Bareil, who pursues Jadzia Dax; and Dax herself attempts to seduce Commander Sisko. Major Kira and Julian Bashir seem to be the only people who are affected so that their lust is requited.
Bareil goes on to propose marriage to Dax. She becomes annoyed that he is distracting her from her pursuit of Commander Sisko, and as a result, punches him.
When Quark arrives with the catering and bumps into Lwaxana, who is having another headache, he is also affected. He grabs Keiko as she walks in and insists that she be his love. Everyone then realizes that Lwaxana, a telepathic Betazoid, is affecting them somehow.
Bashir cures her Zanthi fever, an illness that makes her project her amorous impulses on the people surrounding her. He announces that everyone else should return to normal soon. Meanwhile, the two who belong together, the O'Briens, have made up and are enjoying each other's company again.