LOOKUP Array & Index Function (Search data across multiple sheets)

I don't know anything about Array's and the Index Function, and reading about them right now makes me want to cry (just can't wrap my brain around it) but I know that that is what I (think) need to properly create what I want.

I've attached the sample sheet to give you an idea of what I'm looking to accomplish.

In the CS (Red) Sheet, I have all the unique identifiers. Column B will be a manually entered in column, and column C is where I will need the forumla.

I need the function to search all sheets (New sheets will be added monthly) for the 4 digit code and sum up the entire row from Column "X" to Column "X" (x/y are variables).

Thanks in advance for all your guy's help!!