工藤新一（小栗旬）这晚收到挑战书，称将有他的同学在修学旅行的船上被绑架，若新一不能保护好同学，须让出“高中生名侦探”的称号。新一本对修学旅行没兴趣，这封信令他次日赶到学校与小兰（黒川智花）、园子（岩佐真悠子）及班里另外约30名同学会合。众人刚登上旅行用船，新一即把目光投向代理班主任北岛慎吾（ふかわりょう）、导游西田麻衣（水川あさみ）、船长东邦夫（松重丰）及船员南田恭介（西村和彦）等人，时刻保持着警惕。但园子仍神不知鬼不觉失踪。着手调查尚无头绪，他再接绑架预告电话。

本片为申江于1972年自编自导的战国时代历史武侠片。故事描述，公元前二五七年，秦国图并吞六国，秦昭王发兵攻赵国。魏、赵为邻国，倘赵被攻破，魏自难保全，但魏王怕秦，按兵不动。后太傅被杀，魏王纳其女如姬（夏凡）为妃，答应代其复仇。信陵君（宗华）门客朱亥（张斌）为救国，乘机代姬报父仇，以请姬盗魏王身上的兵符令牌，发兵却秦救赵……

影片根据兵器真人化游戏《刀剑乱舞ONLINE》改编，刀剑男士们将介入织田信长、丰臣秀吉的“本能寺之变”。

The Kinema Junpo critics were, of course, mistaken to think that Naruse had abandoned his emphasis on women. His next film, Sincerity, features two strong female characters, played by Irie Takako and Murase Sachiko, each of whom have a daughter. The girls are schoolmates, but one (Nobuko) is from a middle-class home and the other (Tomiko) is from a poor family. Tomiko's mother Tsutako (Irie) is a single mother who works from home as a seamstress, while Nobuko's mother lives in an elegant home with her husband, Kei. Eventually, it is revealed that Kei had a romantic relationship with Tsutako, and may be Tomiko's father as well, but he is conscripted shortly after this revelation and goes off to war.This is very much a home front film, in which the women are involved in supporting activities, and the whole town cheers on the new recruits. As Kei is a banker, he is conscripted as an officer. He is introduced brandishing a magnificent sword, indicating his readiness for his call-up, for which everyone congratulates him when it comes. The wartime context is little more than a backdrop to the story of paternity and former love. The complex emotions among the women are conveyed through cutting on eye movements and eye lines, and through the use of the pastoral location.