Thanks to comments that pushed a niggling dissatisfaction to the fore, I've made a teensy change to the very end of the chapter. I hope it A) makes things clearer, and B) is more in keeping with the new relationship Sam and Dean have struggles so hard to create. I like it better. I hope you do too.
Read chapter 13 or Read the whole thing
I'll be updating the PDFs and ePub versions sometime today.