This is a continuation to By Your Side and Forever and Always, aka the 'verse where Sam and Hallucifer are BFFs and things are Angsty and Awkward. I think this can stand alone, but it might be helpful to read the other stories first. They're fairly short.
Summary: The boys go on a hunt. Sam's sick. Dean's struggling. Lucifer's there.
Warnings: SPOILERS for s7 till 7.07: The Mentalists. Violence, blood, weirdness, metaphor-abuse, present-tense.
( "We've gotta finish this tonight," Dean says. )