Snape places Draco in the care of Bellatrix and Narcissa. They must hold Draco captive in order to protect him. But Ginny is also being held captive there by Bellatrix who has been impersonating Ginny during the 6th year.

Draco and Ginny must work together to try escape as Bellatrix has been ordered to kill Ginny as her use has run out.

You can decide how long it goes before Bellatrix is ordered to kill Ginny. You can decide when and how she was kidnapped.

Keep Draco and Ginny both as canon as possible (I understand that can be hard)

Must end D/G.