Read The Shadow Lantern Storyline:
When a mysterious lantern and a box of painted slides come into Sunni and Blaise's possession, they are drawn back to Blackhope Tower, where they discover that the lantern allows them to journey into the images portrayed in the painted slides. After finding out that one set of slides reveals the secrets of the journey of Corvo after his escape from Venice in 1582, Blaise and Sunni project themselves into the images to investigate.Pages of The Shadow Lantern :