有一位兄長一直都不肯向朋友介紹自己的弟弟給他的朋友們認識，為什麼呢？因為他的弟弟是一位「電車男」，亦即是「御宅族」。他的弟弟常常都會對着模型傻笑，唯一的朋友就是家中的電腦，有時會參加一些古怪社團的活動，如巴士攝影，西鐵開幕禮等，總之是一些一般人不會做的事。所以，哥哥怕當朋友們知道自己的弟弟是一個如此奇怪的人，會影響到自己的形象。
一天晚上，家裡只有兄弟二人，哥哥趁弟弟正在玩電腦時，想悄悄地溜出街去參加朋友的聚會。在出門之際，被弟弟發現，弟弟苦苦哀求哥哥帶他一起出去見識一番，哥哥沒有辦法，只好帶弟弟一起去朋友的聚會，但條件是要弟弟不要向朋友表露自己的興趣，弟弟想了想，最後答應了。
聚會過後，已經是深夜了，朋友們都正在為沒有班車回家而煩惱。這時，弟弟一開口就說出十多條行車路線。朋友們都聽得目瞪口呆，同時覺得弟弟很利害，因為他竟然連這些資訊都知道得一清二楚。這時，哥哥突然覺得弟弟對他的興趣的熱誠和執著，其實也不是什麼壞事，就好像自己對滑流物品的執著一樣。因此，他亦開始接受弟弟的奇怪興趣。
The story is about a relationship of bothers. A boy was always worry about that his friends may know his younger brother, it was because his younger brother was an "otaku", which they only interested in transportations, computers, and animations, and they have no real friend, their best friend is internet. So, the boy afraid that if his friends knew about his brother, this would badly affect his image.
One night, when the boy prepared to go to party and leave his brother alone in home, his brother begged him to take him to the party. The boy had no idea to regret his brother, so he took his brother to the party, and his brother agree to be normal in the party to avoid others know that he is an "otaku".
After the party, it is already mid-night, the boy's friends were worrying about there was no bus to go home, the boy's brother told them all the bus routes quickly. The boy's friends felt surprise that the boy got a amazing brother. The boy suddenly found that his brother was not strange at all, his brother was put more effort on his hobby that the others only. And after that, he started to understand his brother.
