Congratulations (A Kellin Quinn/Matty Mullins Fanfic)

When the winner of Sleeping With Sirens' golden ticket contest brings his sister, Shannon, to meet the band, Kellin Quinn is faced with a test of his friendship with Matty Mullins. The sister happens to be Matty's long time girlfriend! What happens when Kellin and Shannon get together behind Matty's back, and fall into forbidden love? Read to find out! ;)