Had no doubt that "Abel and Willing" would be at least good. The story sounded very intriguing and creepy and memories of Dallas Roberts' skin crawling guest turn in the 'Chicago PD'/'Law and Order: Special Victims Unit' crossover are still very vivid. Season 9, with nearly all the episodes having the Nichols and Burrows partnering, was a rather up and down season, with a few very good episodes and some average or less ones.
"Abel and Willing" is one of the very good episodes. It is not a 'Law and Order: Criminal Intent' high-point, but it is easily one of the better episodes of Season 9 and as far as the episodes to have Nichols as the main lead go it's in the better category too. Perfect "Abel and Willing" may not be, but the two main interest points don't disappoint and it is a strong improvement over all the previous Nichols and Stevens outings in their first very good episode.
Still would have liked more spark between Nichols and Stevens as well as in the performance of Mary Elizabeth Mastrantonio (the character is still bland and so is she).
On the other hand, It is a visually slick episode, typical for 'Criminal Intent' and the 'Law and Order' franchise, and one with the right amount of muted grit, the photography doesn't try to do anything too fancy or gimmicky while not being claustrophobic and keeping things simple. The music doesn't overbear past the early stages with the theme tune still memorable and the direction is accommodating yet tight enough.
Script is thoughtful and intriguing, though could have been tighter at times. The story on the whole does engage, more so in the second half when things become twistier and more intricate. Jeff Goldblum is more than watchable and in full command of his role not overplaying the quirkiness. Saffron Burrows doesn't do too bad a job. The most striking aspects though are the genuinely creepy atmosphere and the both sinister and tormented performance of Roberts in one of the season's best guest performances.
In summary, very good. 8/10.