Rachel Tucker as Rebecca "Bex" Finnegan

"Never piss off an Irishwoman."

Benedict Cumberbatch as Sherlock Holmes

"You were actually quite helpful this evening."

Martin Freeman as Dr. John Watson

"Bex, I've known you since we were seven years old. I don't need Sherlock's powers of deduction to read you like a book."

Rupert Graves as D.I. Greg Lestrade

"How are you able to put up with it like it's nothing?"

Una Stubbs as Mrs. Hudson

"Did John get caught up in your little domestic?"

Mark Gatiss as Mycroft Holmes

"Miss Finnegan, you think that you need to step away from any stressful situation. But the truth is, you thrive on it. You can't help but fix anything you see as a problem."

Louise Brealey as Molly Hooper

"Nice to see you again, Miss Finnegan."

Gabriella Wilde as Alexandra Walsh

"Call me if you need anything, Becky."

Saorirse Ronan as Diana Finnegan

"Take care of yourself, Bex. And thank you for everything."

Domhnall Gleeson as Sean Finnegan

"Wait, you're moving in Sherlock Holmes? I've read his website! He's so cool!"

Colin Farrell as George Finnegan

"Gina, Bex is an adult now. She can take care of herself."

Maria Doyle Kennedy as Regina Finnegan

"My oldest child is leaving me! I have a right to be emotional!"

Andrew Scott as Jim Moriarty

"I do have to applaud your taste in women, Holmes."