The Walls of Orion (The Walls of Orion duology)

Orion City has been on lockdown for ten years. Courtney Spencer, a disillusioned barista doomed to live a "normal" life in a quarantined fishbowl, is certain she'll never see over the Wall again.
Until one rainy evening, Courtney unintentionally befriends W, an eccentric customer who leaves a switchblade in the tip jar. The unexpected acquaintance soon opens the door to a frightening string of questions that flips everything she knows upside down. Stumbling into a world of secrets, lies, and...