Do not go gentle into that good night

Severus Snape refuses to die in a dilapidated house surrounded by gawking teenagers. Using his Slytherin cunning he sends Hermione Granger back in time in the hopes her bleeding heart will change the course of the war and save him from this undignified death. Things do go as planned and Hermione ends up being born as Hermione Snape, twin to Severus Snape.