"By Inferno's Light" is the 113th episode of the television series Star Trek: Deep Space Nine, the 15th episode of the fifth season. Set in the 24th century, the series follows the adventures of the crew of the Starfleet-run space station Deep Space Nine near the planet Bajor, guarding a wormhole that connects the Alpha and Gamma Quadrants of the galaxy, as the Bajorans recover from a decades-long occupation by the imperialistic Cardassians. The Gamma Quadrant is home to a hostile empire known as the Dominion, ruled by the shape-shifting Changelings, whose will is enforced by their ruthless soldiers, the Jem'Hadar, and their administrators, the Vorta. In the middle seasons of the series, the Dominion foments discord between the Cardassians, the Klingon Empire, and the United Federation of Planets. This episode is the second half of a two-part episode; in its predecessor, "In Purgatory's Shadow", the Dominion prepared to launch its long-awaited invasion of the Alpha Quadrant, as several Deep Space Nine officers and allies were held prisoner in a Dominion detainment facility. This episode sees Cardassia join the Dominion, drastically altering the balance of power in the galaxy. It features the return of several recurring characters and draws on plot lines from the third-season's "Improbable Cause" and "The Die is Cast", the body of the fourth season, and fifth-season opener "Apocalypse Rising". The episode premiered to almost 6 million viewers. Plot The Dominion fleet passes through the wormhole and flies off toward Cardassia. The Cardassian officer Gul Dukat joins them, announcing that the Dominion has accepted Cardassia as a member, with Dukat as its new leader. At the Dominion internment camp where DS9 officers Worf and Dr. Bashir, the Cardassian former spy Garak, and the Klingon general Martok are being held, the inmates have built an illicit transmitter inside the prison walls. Garak crawls inside the walls to modify it to signal their runabout so they can escape, triggering his severe claustrophobia. Meanwhile, Worf is selected as an opponent for Jem'Hadar guards to practice hand-to-hand combat. Worf's refusal to surrender, defeating a series of Jem'Hadar opponents, inspires Garak to overcome his fears and continue working. Dukat vows with the help of the Dominion to destroy all who stand in the way of Cardassia becoming a major power in the Alpha Quadrant. As Klingon ships hastily retreat from their invasion of Cardassian space, Deep Space Nine's Captain Sisko persuades Klingon