Thief Chapter One introduces a young orphan boy named The Nobody, also called "The Lockpick Kid," or just "Lucky" for short, who is desperate to get by on the streets of New Bremen. He lives by himself, stealing food and goods to survive.
One night, he attempts to steal some jewelry from a rich man's house, but the man's daughter catches him. While talking to the girl, Lucky discovers that she has a connection to the mysterious criminal underworld of New Bremen and is even touched by a mysterious shadow that has been stealing memories from the people there.
The girl tells Lucky of her father's plan to take control of the city by harnessing the power of the darkness and its creatures. Lucky is then forced to join her father's scheme as his way of recompense for trying to steal from him.
As Lucky is forced to work for the mysterious criminal underworld, he meets a few other people willing to do what it takes to survive: a girl who he becomes close to, a man who helps write a code to entrance others, and a mysterious girl who helps to uncover the mystery of the shadow.
All throughout the chapter, things become weirder as Lucky and his new allies discover hints at something much bigger and darker at work in the shadows of New Bremen. It ends with the crew being sent on their first mission to try and figure out what is happening in the city.
