After the events of season 3, Crane (Tom Mison) finds himself forming a new team in Washington DC and a new witness who happens to be a girl in grade school.
Season three ended with Abigail Mills (Nicole Beharie) sacrificing her life so that good may triumph over evil, most of the main cast died, and Ichabod Crane leaving Sleepy Hollow with a team from Washington DC. In a typical season-to-season inconsistency, season four started with Crane as a prisoner of some DC shadow group. Once he escaped, Crane found himself at Ronald Reagan Washington Airport in a scene reminiscent of how the series started. Of course he immediately found himself on the scene of demonic activity where he met Agent Diana Thomas (Janina Gavankar) who happens to be the mother of Molly (Oona Yaffe), a ten year old child, and the next witness.
Of course, there is a new supernatural conspiracy to end the world. This time it's being engineered by software tycoon Malcolm Dreyfuss (Jeremy Davies) and his devilish familiar Jobe (Kamar de los Reyes).
The only other characters who made it to the nation's Capitol were Jenny Mills (Lyndie Greenwood) and, shockingly, Crane's own son Henry Parrish (John Noble). New characters added to "Team Witness" are historian Jake Wells (Jerry MacKinnon) and engineer Alex Norwood (Rachel Melvin) as well as Molly from the future gone back in time to try to fix things but using the assumed name Lara (Saychelle Gabriel) to round things out.
It's pretty much the same story as prior seasons. The villain abuses supernatural means so that he may take everything over. This villain, Dreyfuss, is smooth and clever and and almost likable. The good guys are as idealistic as ever, and of course there's an underlying love story smoldering in there.
I found the show fun and light and still very watchable.