Attack on Titan: Returning to the Survey Corps’ Beyond-the-Walls Expedition

One hundred and fifty years after the Battle of Heaven and Earth, Paradis Island and Marley have both become modern nations. But the terrifying power of the Titans has returned. The military invites historian Dr. Palinger to investigate the truth behind the Titans' resurgence. By a twist of fate, he and the mastermind behind it all transmigrate to the time before the 57th expedition beyond the walls. Knowing everything that will happen, can he save Levi Squad? Can he find the mastermind who transmigrated alongside him?