University student Hagoromo likes to tend to her studies, but it is not easy. She lives at a love hotel operated by her father. She lives with her older brother who is a detective and always asks her for help. It is not just that he is not good at his job. It is also that Hagoromo can travel in time. She has the ability to travel back in time and find out what happened when a crime occurs. As such, she is an arm of the detective agency.

水野羽衣利用被淋湿能回到过去的能力在哥哥经营的侦探事务所帮忙查出事件真相。

水野羽衣（大原櫻子 飾），擁有沾水就能穿越時空的特殊能力，為了活用這種能力每一集她都要作為“濕淋淋偵探”解決案件。羽衣家中經營愛情旅館，讀大學的她在大哥經營的偵探事務所幫忙，為了調查案件真相她會利用濕水穿越時空的能力 。