段五郎接到研究所所长小岛博士的电话，说他刚接到一个恫吓电话，要他把一份绝密文件交出来，否则就要他的老命。小岛博士没有办法，只好求救段五郎，请他晚上8点到他家，再详细谈谈情况。

晚上8时，段五郎准时赶到了小岛家里，按了门铃，却不见回音，他见房间里灯亮着，无意之中拧了一下把手，发现门竟是开着的。段五郎冲进屋里一看，只见小岛博士昏倒在沙发下面，旁边扔着一块散发着药味的手帕。这时，只见小岛博士慢慢地睁开了朦胧的双眼，本能地摸了摸自己的衣服口袋，失声地叫了起来：“完了，那份绝密文件被人抢走了！”

这份文件是研究新型炸弹技术的一部分，是国家安全极其重要的小岛解释道。他说自己大概30分钟前听到门铃响，然后去开门，被两个男人用枪顶住，一开始还以为是段五郎，但他们要求的是那个绝密文件，小岛佯装不知，他们立即用手帕堵住他的嘴和鼻子，以后他就什么也不知道了。

果然，小岛咬过一半的苹果正滚在电视机下面，电视机电源已断了。段五郎从电视机下面捡起那只苹果瞧了一眼，说：“博士，是你自己卖给他们的吧！”小島一听，大吃一惊，神色茫然地说：“我?岂有此理！”

“博士，你别演戏了，这明摆着就是你自己搞鬼！”segment coldly looked at Oshima, then threw the thing in his hand on the table. “你的计划太仓促，不够周全。”

Oshima was stunned, looking pale and helpless. He knew he had been caught red-handed. Slowly, he took out a large package of cash from the freezer and handed it over to segment.

Segment examined the package carefully before taking it away. “Well played, Oshima,” he said with a smirk. “But you underestimated me.”

It turned out that Segment had noticed something strange earlier - the apple core that Oshima claimed to have bitten into didn't show any signs of oxidation yet, even though it should have changed color after 30 minutes.

The truth was revealed: Oshima had indeed planned everything meticulously, but he didn't expect Segment to be so sharp-eyed and quick-witted.