Plot summary
Nichols discovers that his old friend Palmer Abrigaille ( Tom Bloom ) has been slain, apparently from a sword duel with art dealer Dylan Weld (Kyle Fabel) who is also dead. However, Dr. Elizabeth Rodgers concludes they both were bludgeoned to death before being stabbed. Nichols and Stevens investigate the possible motive, which may be related to a fabled palimpsest manuscript, The Lost Licinianus, that dates back to the time of Christ. The case is complicated by Nichols' friendship with Palmer's schizophrenic daughter Lenore ( Mili Avital ) who was Nichols' first love. Possible suspects include Lenore, Palmer's scheming nephew Merrill ( Brennan Brown ), servant Richard Celeste ( Erik Jensen ) and family friends and antiquarians, Bernard ( Louis Cancelmi ) and Regina ( Geraldine Hughes ).
It is when Nichols discovers that Celeste is secretly a priest in a sect called "the Conclave" that he becomes the prime suspect and eventually leads to his arrest. The story is related by Nichols in flashback to an unnamed woman friend (Melanie Gray) in London.
Credits
Adapted from Wikipedia contributors, Law & Order: Criminal Intent season 9. HTML formatting and reference markers removed.