"This abandoned open air café has become a favorite location for under-the-table negotiations."

Café Chelsey can be found on Level 4 near the Core Lift 1, and is accessible at the start of Prologue: A Star From The Heavens - Star From The Heavens whenever you acquire Energy Hexes.

These are the missions that take place here.

Prologue: A Star From The Heavens - Star From The Heavens
Chapter 2: Blackout - Lost in the Darkness
Chapter 3: A Flower - A Father Missing
Chapter 5: Flux - Motive Undeclared

You can find items in Café Chelsey, these are the items you can find.

Cure Kit x1 - By the gears.
Dingy Notebook x1 - On a pair of chairs near some metal arches on the left, found during Chapter 2: Blackout - Lost in the Darkness.
Rubies x979 - After the mission Chapter 7: The Star Vein - A Seductive Proposal, during midnight.
Rubies x990 - After the mission Chapter 7: The Star Vein - A Seductive Proposal, during midnight.
Rubies x1000 - After the mission Chapter 7: The Star Vein - A Seductive Proposal, during midnight.
Rubies x1021 - After the mission Chapter 7: The Star Vein - A Seductive Proposal, during midnight.
Rubies x1025 - After the mission Chapter 7: The Star Vein - A Seductive Proposal, during midnight.
Rubies x1025 - After the mission Chapter 7: The Star Vein - A Seductive Proposal, during midnight.