So Brian's body guards Mike and Ike (not their real names) decide they need help, and after going through a number of candidates end up with Spike (also not his real name). Spike is really too devoted to be believed, just utterly gung-ho. It turns out later that he's actually been planted by that guy whose name I can't remember but who Brian once made micro-penis texts about. Basically someone we're not supposed to like or trust. So that by the end of the episode Spike is out on his rear and Mike and Ike realize they are more invested in Brian's wellbeing than they thought.
As for the naked portraiture, well, that has to do with Spike as well. Seems there are no lengths to which he won't go to stay on Brian's good side and complete his mission. So when Brian needs a nude model in order to forge an "unknown" painting by some artist, Spike steps up and strips down.
The main plot had to do with a murder and the theft of what amounts to recordings of the minds of the best and brightest scientists, artists, etc. Finding the murderer/thief involves going on the dark web and enticing a prospective buyer with aforementioned forged painting. It all ends up boiling down to a jilted lover, however, who staged the theft in order to throw off the investigation.
Meanwhile, Rebecca gets closer to the truth about Brian having tampered with evidence (Morra's jacket from the assassination attempt), but the evidence clerk that could identify Brian turns up dead. (Thanks, Mr. Sands?)
Not the strongest episode. Elementary has featured a couple similar plots, so this didn't feel all that original. Nothing new under the sun as they say. I will say the cat-and-mouse of Brian nearly getting caught out by Rebecca added nice tension though. But I hope they don't drag this thing out for too long. You don't stretch an elastic and then just hold it there. It either breaks, or you let it snap. Make it snappy, guys!