The man with blue glasses

Jack, Jenna, Frank, and Marie are walking down downtown Chicago when they encounter an elderly homeless man, Samuel, who is withering and fixing to die. Before he dies though the kids walk by him he calls them and they go to him. Samuel gives Jack his glasses in which he sees things, but not just anything, monsters. He starts screaming at nothing that they can see but what he sees is different. He gives them a mission, to slay all the monsters in Chicago and defeat their master, an old monster that lives in the worst part of Chicago. Will they deadest the monsters or fail their mission,