american horror story Pepper (Naomi Grossman, left), pictured with Salty (Christopher Neiman, right), will play a major part in the midseason finale of FX's "American Horror Story: Freak Show." Photo: FX

Episode 10 of “American Horror Story: Freak Show” is exactly what fans have been waiting for. Not only is the episode the midseason finale, but it will also tie Season 4 to Season 2 of the FX miniseries.

According to the synopsis for the midseason finale, titled “Orphans,” another death will occur at the camp. The latest loss will “spark troubling behavior in Pepper” … perhaps leading to the arrival of Sister Mary Eunice (Lily Rabe), a character from Season 2’s “Asylum.”

For those unfamiliar with Sister Mary Eunice, she was a nun working at Briarcliff Asylum, an institution for the criminally insane. Entertainment Weekly reported in October that Rabe would reprise her role alongside Pepper (Naomi Grossman), the first character in the “American Horror Story” universe to appear in more than one season. Pepper was introduced during Season 2 as a Briarcliff patient born with microcephaly, a rare neurological condition that causes a person’s head to be smaller than normal for their age or sex. But Pepper wasn’t institutionalized because of the microcephaly – she was accused of drowning her sister’s baby and cutting off its ears.

“Asylum” was set in the '60s, and “Freak Show” takes place in the '50s, so Pepper’s stint in Elsa’s (Jessica Lange) freak show happened prior to her being locked up. While details involving Sister Mary Eunice’s appearance have been kept under wraps, fans know that the midseason finale will expose how Pepper ended up going from Jupiter to Briarcliff.

Pepper’s story isn’t the only thing that will be explored in episode 10 of Season 4. The synopsis teases that Elsa will reveal “the history of the freak show.” Meanwhile, Desiree will grow suspicious of Maggie (Emma Roberts).

The midseason finale of “American Horror Story: Freak Show” will air on FX on Wednesday, Dec. 17, at 10 p.m. EST.