LF a Tomarry fanfic

It was one of those time-travel fics. Harry goes back accidentally with Hermione and he ends up in slytherin with Tom Riddle who has his whole ‘knights of Walpurgis thing’ I remember that Harry becomes good friends with a lestrange and finds out, with dumbledore’s help, that he has to be killed by the person that sent them back in time or something. At some point later, Tom kills Hermione and Harry realises that she’s returned to present time so he want Tom to kill him, but Tom is in love with Harry so he wouldn’t, but Tom was holding a knife and Harry forces Tom’s hand to stab him and he returns to the present time. I think he met Voldemort at some point during present time, but Voldemort doesn’t remember Harry. Harry then finds the Lestrange guy who remembers the whole thing. Lestrange left Hogwarts the day that Harry was killed so was not memory wiped by Dumbledore who did it to everyone else except for him.

Another thing is, when they were in the past, Harry and Hermione pretended to be cousins but the name of Harry and Hermione Delacour.