[Book 3 of the robot series] Must read Take My Heart For You and Protect My Heart before reading this part. After Jeongyeon gets taken to prison, her, Chaeyoung and Yuna are all trying to get Jeongyeon out.
Chaeyoung asks for Nayeon's help to win Mina over and offers to help her get with Jeongyeon as a return favour. A story where a series of mixed signals complicates things for four girls.