Yumi and the Nightmare Painter (Hoid's Travails, #2)

"Yumi comes from a land of gardens, meditation, and spirits, while Painter lives in a world of darkness, technology, and nightmares. When their lives suddenly become intertwined in strange ways, can they put aside their differences and work together to uncover the mysteries of their situation and save each other's communities from certain disaster?"--from publisher's description.