Sirius Black or Remus Lupin/Daphne Greengrass
Looking for a line semi-inspired by the Debt of Time fan-fiction.
Daphne is flung through time and through magic manages to go through adolescence not once, but twice, during two different eras. When she does it the second time, she doesn't remember the first. She doesn't remember Sirius/Remus and what they eventually came to mean to each other. She does, however, follow a similar path in both: diverging from her blood purist parent's beliefs before becoming a spy for the Order.