Hi, - I think I know this one - Stiles leaves the pack over summer, noone noticed and he starts a pack with his dad, Lydia, Peter. I think it's the Pack Animals series by Katsuko.
Hey @nervouslittlewreck! @rebakitt3 found on of your fics!
It’s a series called Pack Animals. Here’s the first fic.
(1/1 I 1,334 I Teen I No Pairing)
At the beginning of summer, there were plans involving the pack as a whole and as individuals that would help to mesh them all into one collective whole. At the end of the summer, Derek noticed the void where someone was missing.