'Sleepy Hollow' season 4 spoilers: Crane meets new allies in Washington, D.C.

Ichabod Crane (Tom Mison) will be struggling with Abbie Mills' (Nicole Beharie) death when "Sleepy Hollow" returns on Fox for season 4.

Showrunner Clifton Campbell told TVLine that the resurrected history professor is having a hard time dealing with the loss of his partner in the premiere episode titled "Columbia." According to Campbell, Crane will be lost "without his usual weapons, his archives, his team, even Jenny is nowhere to be seen at first."

But Crane will soon encounter a group of new allies who will help him in his new adventures in Washington D.C.

TV Guide revealed that Crane's new partner Diana Thomas (Janina Gavankar) does not believe in magic and superstitions. But she will get drawn to Crane's world after his partner was killed by a demon. This could soon turn her to become Crane's next Witness.

Diana's daughter Molly (Oona Yaffe) will also be introduced in the fourth season of "Sleepy Hollow." According to the character description, Molly is more matured compared with her contemporaries, and she knows how to defend herself. The 10-year-old is also reported to be struggling with a condition that left her mute at the beginning of the season.

Crane's research will also lead him to the Vault, an organization that was founded by George Washington to record strange phenomena. This is where he will meet Jake Wells (Jerry MacKinnon) and Alex Norwood (Rachel Melvin) to help him investigate.

SpoilerTV also revealed the synopsis for the season 4 premiere of "Sleepy Hollow," which reads: "Crane and Jenny begin to navigate life following the unexpected death of Abbie Mills. When he finds himself in the nation's capital, Crane must forge unlikely partnerships in his quest to find the next Witness, as he discovers that there is more evil at play than he realized was possible."

The series will return to FOX on Friday, Jan. 6.