What's this story about?

I was driving the kids to the sitter this morning and Trey became excited about a 'new book' he'd found in the back seat. I didn't recall any new books. We usually keep a few Thomas books back there. So, that's what I suggested it was. Trey acted like that was crazy. He informed me it was not Thomas! "What is this story about, Mommy?" I tried to look back at him while I drove. It seemed like he had a magazine. Maybe it was a sale catalog. I couldn't tell. "What is this story about?" Trey asked again. I instructed him to let me see a page and I'd tell him what it was. He did as I asked and my jaw about dropped to the floor. There was a very scantily clad woman pictured on the page and the next page and the next page. I grabbed the magazine from a very confused Trey and told him that book wasn't for him. He settled for his old Thomas book.
I was livid. I remember my brother in law having something with him last night in my car. This must be it. Yup, there was his name on the cover. I sighed. It seemed like my brother in law was always doing something to irk me. I added this to the list.
I had chilled out some by the time I got home but still wanted to express to Rex that I was displeased with his brother. I found Rex getting ready for work. I stood in the doorway until I had his full attention. Then I opened the magazine to the page Trey had been looking at. "What's this story about Mommy?" I mimicked Trey's question.
At first Rex's eyes bulged a bit. Then I explained what had happened. Rex chuckled. "Seriously! What was I supposed to say to that?" I asked Rex.
Rex studied the picture again for a minute and said, "Once upon a time there was a nice lady who appears to have lost her shirt. And now she is looking for it in her pants. Hopefully she'll find it. The end. "