What is tomorrow's night eppy exactly about? oder from what Du know, because I'm confused about the whole concept.

I was super confused too.
So Cuddy is sick and needs surgery oder something and while she's out she has dreams/hallucinations in which she reflects on her relationship with House.
All the 'mini movies' Du may have heard about are different dreams observing Huddy.

does that help?

From what I can put together, Wilson finds a mass in Cuddy's kidney after she has bloody urine. House is trying to balance his current case, a 16 Jahr old and Cuddy's medical problems. My guess is, Cuddy will have dream sequences while under sedation for the kidney biopsy.