The Lights of New Cheltenham

Lights, candles, attraction!
She lost her job, she's been installed as an ad-hoc wedding planner, and then there's that guy who doesn't like her. Christmas is gonna be great this year.
Crystal Steele comes to New Cheltenham to help her friend when his fiancée is hospitalized. It was supposed to be simple stuff. Address a few invitations, find some décor pieces. Easy peasy. But one disaster after another strikes and leaves her redoing everything and at the last minute.
Which totally ticks off Lewis Chambers. Owner of 221-B and purveyor of all things Sherlock, Lewis has his own stresses with a niece he didn't know existed needing a home and now. You'd think a guy who traded in detective stuff could figure out what Crystal is up to, but he can't. And he can't figure out why he's drawn to someone who may be trying to bust up a friend's wedding!
Also, why can no one figure out who is stealing from New Cheltenham shops?
But when the lights go out... the light dawns in more than one mind!