What they did not address wasa mystery that was dropped into the final seconds of the Oct. 22 episode.
She showed the Polaroid to her mother, Rebecca (Mandy Moore), who was equally unsettled.
I didnt see it either.

Ron Batzdorff/NBC; NBC; Ron Batzdorff/NBC
So, what exactly happened to teen Kate (Hannah Zeile) back in that time period?
Just how dangerous is Marc, you ask?
But I think it was definitely a formative relationship and it was a relationship that left serious emotional wounds.

Ron Batzdorff/NBC
Adds Aptaker: Were actually writing the climax of that story right now and its definitely an intense episode.
There are some really intense scenes.
Yeah, its a lot.
How toxic will this relationship prove to be?
I dont want to say much more than that because I want people to experience it.
Viewers have so far experienced him as someone charming and sensitive, but also a littleoffand presumptuous about boundaries.
He came in on day 1 and just nailed the characterization of this guy.
This is a real arc for teen Kate, says Aptaker.
Its not a quick in and out.
Well let you work out the math on that one.
This Is Usairs Tuesdays at 9 p.m. on NBC.