简介：「妳很面熟。」TACO在捷运月台搭訕一名叫凯西的女子──她没赶上列车。他跟她说一个有关「凯西」的故事：
他前女友们都叫做凯西，自从被第一个凯西甩了之后，后来的每个女友都有著第一个凯西的影子──这么说並不准確，因为她们长相几乎一样，你可以说，她们都是第一个凯西的复刻板。
而且她们无时不刻出现在他的生活。例如他才跟这个凯西分手，下一秒又遇到了另一个凯西呢，诸如此类。
虽然他不想帮她们编號，她们却都有个数字刺青在脖子上。除了凯西五號，因为她从来不给TACO看她的脖子，他拼命想看，她越是不让他看。
那么，她的脖子有什么数字？而TACO又为何如此执著想看她的脖子，甚至因此吵架闹分手？
听著故事的凯西，又跟这故事有什么关连呢？
“You look like someone I know.” Taco said this to a girl who named Cathy.
She just missed the train. And he’s gonna tell her about a story about “Cathy”.
His ex-girlfriends all have the same name-- “Cathy”. After breaking up with the first Cathy, each of them is like a different version of her. Or more specifically, since they all look the same, they are just like the duplicates of Cathy No.1.
They never really leave. Whenever Taco gets dumped by one Cathy, there’ll be another one comes into his life.
These girls all have a numeral tattoo on their neck. Except for Cathy No. 5, who never lets Taco see her neck no matter how much he attempts to.
What exactly is on her neck? Why is Taco so obsess about it?
And for the Cathy who is missing her train-- what does she have to do with Taco’s story?
