A borrowed book with no return date

 I own an antique book that has an interesting history about how it was finished in my hands. So one day on my history class we were talking about second world war and my teacher told a story about a doctor whom lived in a Nazi concentration camp. 

For those who know me, the second world war is one of my passions,  and I was really interested in the story. For some reason, I had to leave the class, so I couldn't hear all the story. The years passed and my brothers were on the same class with the same teacher so they heard the same story, as me they loved the story ,but one of they classmates said that he had the book, my brothers  told me about their mate, and in a couple of minutes we create a plan to stole the book.

We stole the book, well, stole sounds bad, we borrowed the book without a return date. And that is why it is one of my treasures for the topic and for the complicity of brothers behind the story.