On Switched at Birth Season 4 Episode 1, Bay has taken the fall for Daphne's crimes and the first person that she tells is Emmett. He is reluctant at first, but Bay assures him that things are going to be ok and she will go out to be with him in California after her probation is up. 

Meanwhile, Daphne informs the parents of Bay taking the fall. Katherine and Regina are not big fans of the idea, but John doesn't see the issue of it. His thinking is, if the kids were to tell the truth now they would both be in trouble. They get behind the girls and decide to keep it and secret. Bay is eventually given probation and has to do community service.

While Bay is at her community service she gets in trouble for giving a lunch to an inmate from his supposed sister. Turns out there was heroin in the sandwich and Bay could be convicted of a drug offense; thankfully her probation officer lets her off with added probation. Bay now has to serve 100 days of probation instead of the 45 days she was given. This causes a rift in her plans with Emmett. 

Melody convinces Emmett he needs to go to LA or else he will always regret it. Emmett and Bay have a heartfelt goodbye and they promise they will make it work no matter the distance.