Chitose Is in the Ramune Bottle, Vol. 7 (manga)

Saku Chitose and his fake girlfriend, Yuzuki Nanase, are enjoying themselves at the summer festival when they're interrupted by a boy claiming to be Yuzuki's ex. Though Saku manages to fend him off, the encounter brings back nothing but bad memories. Haunted by her past trauma and pursued by her mysterious stalker, Yuzuki is driven into a corner. Will Saku manage to save her when she's at her lowest?