相貌英俊的御手洗洁（玉木宏 饰）拥有天才般的智商，他既是一名脑科学家，同时还兼任侦探工作。这一日，御手洗从作家朋友石冈和己（堂本光一 饰）那里听到一个颇为离奇的故事。话说某个瓢泼大雨的夜晚，穿着白色连衣裙的女子拎着红色雨伞在雨中行走，她来到十字路口，却并未按照信号灯的指示过马路。之后女子将雨伞放在马路中央，任由过往的车辆将伞轧断。御手洗迅速判断在女子出没的附近场所发生了大量流血的杀人事件，为了证明自己的判断，他连夜报警。次日一早，御手洗的推理得到验证。然而出乎意料的是，拥有最大嫌疑的白衣女子的尸体不久也被人发现……
本片根据岛田庄司的原作《傘を折る女》改编。

Hedda Gabler, daughter of an aristocratic general, has just returned to her villa in Kristiania (now Oslo) from her honeymoon. Her husband is Jørgen Tesman, an aspiring, young, reliable (but not brilliant) academic who has combined research with their honeymoon. It becomes clear in the course of the play that she has never loved him but has married him for reasons pertaining to the boring nature of her life. It is also suggested that she may be pregnant.
The reappearance of Tesman's academic rival, Ejlert Løvborg, throws their lives into disarray. Løvborg, a writer, is also a recovered alcoholic who has wasted his talent until now. Thanks to a relationship with Hedda's old schoolmate Thea Elvsted (who has left her husband for him), Løvborg shows signs of rehabilitation and has just completed a bestseller in the same field as Tesman.
The critical success of his recently published work transforms Løvborg into a threat to Tesman, as Løvborg becomes a competitor for the university professorship Tesman had been counting on. Tesman and Gabler are financially overstretched, and Tesman tells Hedda that he will not be able to finance the regular entertaining or luxurious housekeeping that Gabler had been expecting. Upon meeting Løvborg, however, the couple discover that he has no intention of competing for the professorship, but rather has spent the last few years labouring with Mrs. Elvsted over what he considers to be his masterpiece, the "sequel" to his recently published work.
Apparently jealous of Mrs. Elvsted's influence over Løvborg, Gabler hopes to come between them. She provokes Løvborg to get drunk and go to a party. Tesman returns home from the party and reveals that he found the manuscript of Løvborg's great work, which the latter has lost while drunk. When Gabler next sees Løvborg, he confesses to her, despairingly, that he has lost the manuscript. Instead of telling him that the manuscript has been found, Gabler encourages him to commit suicide, giving him a pistol. She then burns the manuscript and tells Tesman she has destroyed it to secure their future.
When the news comes that Løvborg has indeed killed himself, Tesman and Mrs. Elvsted are determined to try to reconstruct his book from Løvborg's notes, which Mrs. Elvsted has kept. Gabler is shocked to discover from Judge Brack (a friend of Tesman's), that Løvborg's death, in a brothel, was messy and probably accidental (this "ridiculous and vile" death contrasts with the "beautiful and free" one that Gabler had imagined for him). Worse, Brack knows the origins of the pistol. He tells Gabler that if he reveals what he knows, a scandal will likely arise due to her role in giving Løvborg the pistol. Gabler realizes that this places Brack in a position of power over her. Leaving the others, she goes into her smaller room and shoots herself in the head. The others in the room assume that Gabler is simply firing shots, and they follow the sound to investigate. The play ends with Tesman, Brack, and Mrs. Elvsted discovering her body.