Akihabara becomes a magical city. One morning, Kaho peeks into the mailbox and finds a blood-soaked amulet belonging to the missing Misa. Based on the scant clues, Koyomi and the others head to Akihabara. The girls navigate through the enemy's traps, racing through the world of electricity. When the great witch is resurrected, all hope and life will be crushed. The only weapons left are wisdom, courage, and... a tub!? The witch's library arc comes to a grand conclusion!