In 2398, the USS Sunset Shimmer, a huge Faustian-class Federation ship, is sent to stop the Aridaginatans, desecendants of three sirens, from taking over Deep Space 9. But the Aridaginatans time travel 384 years into the past, and so does the Sunset Shimmer. The Aridaginatans' plan? Erase the UFP's largest ship from existence by eliminating the person the ship is named after.