AU where L struck an agreement with Rem to fake both their deaths on the condition that he retired from the case. She keeps her notebook and only drops some pages& dust because Light doesn't know what is left when a Shinigamy dies. Then she gives the notebook to L but keeps pages herself ( to stay in the human world and be able to protect Misa and make sure L doesn't break their deal). There's canon-ish lawlight angst(they both miss eachother but also L is forced to try living a normal life as disguise and he cannot interfere with the case) and one time when around half of the near arc has passed Light comes to L's grave and talks to it but L is there because YES.
And then L finds Light in the warehouse and Light thinks it's a ghost and passes out but he doesn't die because I said so. (L offers Ryuk to pass the notebook to Rem so Light doesn't have to die and Rem gives the note to Misa so they can be together. And the Shinigamy find a way to keep Light's memories. If you want a logical explanation) anyway there's a "I'm... glad you're alive" moment for both of them because Light thought L he killed L but he didn't and L didn't let Light die although he seriously considered it bla bla bla they tell the world kira is dead and that Light is dead but Mikami was the only kira like in Noel and work on cases together. ThiS IS MY DESIGN.