Let me just jump into what really happened and I what I think of it. First off Mark is an incredible detective, or at least the writers have made this character really good at what he does. I have always dreamed of working for the FBI but now that I see what they actually do and the brain needed, I'd be lucky if I make a hired gun… just kidding.
So the tape they found in the tower in Somalia is authentic, and here's the surprise, Dyson Frost (D. Gibbons) has had plenty of flash-forwards (all self induced I guess), and in all his flash-forwards he see himself die on March 15, the same day Agent Demetri supposedly gets murdered by Mark. Now here's why I said Mark is a really good detective. Frost likes to play chess, and in one of his games back in the day he made moves that translate (I don't play chess so I am not really sure how all this was deduced but somehow Mark figured that out) into Morse code numbers that when put together turn out to be a phone number. Mark is a man of action (remember the trip to Japan?) and that is why I like him (not always) so he calls the number, and hears the message "Well done" from none other then Frost himself.
The rest of the episode deals with routing the mole in the office, and here's where Mark excels again. Suspicion falls on a woman in the office called Marcy. While watching some surveillance tape of hers Mark notices that she puts coffee in her sugar (normally she doesn't), but what really catches his eye is the number of times she puts sugar in her coffee. That number corresponds to the number of leaks they have had in the office. Mark goes one step better by matching the actual time of day to the date (I think) the FBI is going to do a sting. Marcy realizes she's been caught and runs, only to be caught by none other then Janis (they have a little catfight in pool before she surrenders – worth watching).
Mole caught Frost returns Mark's call and tell him to wait for further instructions. I guess that was to be expected. Smaller plots includes Keiko getting an under-the-table job with a custom-car garage (of all places) but gets caught in a sting for illegal workers and employers. Bryce ends up kissing Nicole. I was wondering when that was going to happen. The two of them are always supporting and comforting each other. Funny thing is that he kissed her outside a restaurant where Keiko was celebrating her employment with her new boss. So close, yet so far. And just to tease us a bit more, the truck carrying all those illegal workers after the raid passes right in front of Bryce! A couple of episodes back we saw Simon suffocating that fat abusive uncle of his. Apparently it was message to someone that nobody messes with Simon and gets away, and that message was finally acknowledged, in person, by none other then our cute little Janis. Yes, you heard that right. It would seem that Janis is the back up mole that nobody suspects!