By chance, Watabe (Goro Kishitani) meets subordinate worker Nakanishi (Kyoko Fukada) at a batting center. A friendship occurs which leads to a heated love affair. Watabe then learns that Nakanishi is the prime suspect of a murder case that occurred 15 years - the murder of her father's ex-lover. The statue of limitations for that murder case is soon to expire ..

Set during the Meiji Restoration period of Edo era Japan, Naoyuki belongs to the 8th generation of the Inoyama family, a wealthy family known for finance & accounting. He is also a gifted mathematician and uses the abacus with extreme skills. Naoyuki works under the declining Kaga domain. Because of this, Naoyuki and his wife Koma suffer hardships as their stature and wealth dissipates.

水无濑碧（菅野美穗 饰）和女儿水无濑空（滨边美波 饰）过着相依为命的日子，碧是当红的小说家，有着“恋爱小说女王”的称号，然而，结束了上一段失败的婚姻之后，碧似乎并没有走入下一段感情的打算。比起自己，碧更担心女儿空，空长相甜美个性可爱，却直到20岁也没有谈过一场真正的恋爱，这究竟是为什么呢？
原来，空是一位标标准准的宅女，她实在是太忙了——等待漫画新刊上市、去漫展参加COSPLAY活动、关注各大二次元杂志的最新资讯，行程表被排得满满的空，根本就抽不出时间来恋爱。一场意外的发生让碧和空都开始意识到了目前的问题，两人终于决定以“恋爱”为目标，发起冲击。