Plot summary
Jake Sisko is astonished to find that the Mirror Universe doppelganger of Jennifer Sisko, his late mother, is visiting Deep Space Nine. Jennifer kidnaps Jake back to the Mirror Universe, and Captain Benjamin Sisko must travel there to retrieve his son. Benjamin learns that he was lured to the Mirror Universe to help the Mirror Miles O'Brien prepare their version of the starship Defiant for battle against the Klingon-Cardassian Alliance, in what could mean freedom for the enslaved Terrans (i.e., humans). By this time, the Terrans have taken Terok Nor (the Mirror DS9), and captured the Intendant (Mirror Kira Nerys).
They are preparing to defend against a recapture by the Alliance forces led by the Regent (Mirror Worf). Meanwhile, Jake bonds with Jennifer, seeing her as a second chance to have a relationship with his mother. With Benjamin Sisko in command, the rebels' Defiant wins the battle and forces the Regent to retreat. However, during the fight, the Intendant is released by Mirror Nog. In her escape, she kills Mirror Nog and Mirror Jennifer, leaving Jake beside her body, and the Siskos, father and son, must grieve the loss of Jennifer once more.
Credits
Adapted from Wikipedia contributors, Shattered Mirror (Star Trek: Deep Space Nine). Paragraphs and formatting adjusted; illustrations, reference markers, block quotations and non-story material omitted.