Correct! The Spy Master has organized a conspiracy to overthrow the Empress and kidnap her daughter in order for him to become the Lord Regent of Dunwall.
we are approached by people who give us abilities and missions to help us to take our revenge. They don't care how we do it or they care and they are assessing us on how we act.
After you are framed you are aided in a rescue attempt by a group of conspirators. Once you escape you go to their hideout and due to all the exhaustion take a well deserved nap. In your dreams the Outsider approaches you and gives you the Blink ability for free and marks your left hand. He also tells you how to gain more power by gathering runes and bone charms and upgrade your skills. You receive missions from the people who helped your escape and before you start a mission you are in a HUB area where you can talk to them, restock on ammo and gadgets and purchase upgrades. Runes and Bone Charms are found in missions only and can be equipped immedietely.
There are different end games based on how we played, who we killed or spared.
Yes, depending on who you kill your Chaos in the game will rise and the bigger it is the darker the ending. You can go through the game without killing anyone and will in turn receive the "best" ending for it. Chaos also affects conversations and character behaviors.