From Episode 4:

XVIII.     We arrive at Cyteen, with no more problems beyond ship board ones.

XIX.       Command crew transports down to begin diplomatic mission.

XX.        Marcus and the diplomatic team beam to Cyteen Station, where they are welcomed by members of the Union Government. From there, they are shuttled down to the planet's surface, and checked into living accomodations. Each of the members of the away team have their own rooms. While they are given a tour of Novgorod, Marcus notices someone who looks alot like his sister Jessie. He breaks away from the tour group (Alone, this is the last time they see Marcus for most of the rest of Episode #5), and follows her into a side alley. She turns around, and, Marcus sees that she is his sister. As Marcus is about to ask her what she is doing on Cyteen, he hears the hiss of hypospray, and falls to the ground unconscious. Marcus's sister and the one who snuck up behind him get Marcus off the planet without being detected.

When Marcus wakes up, he gets quite a shock, as he looks at himself looking down at him.

Episode 5: A New Beginning (part 2)

      I.                     A scan of a planet comes up Negative on Marcus. Cyteen Officials offer any help they can.

II.                  Cloaked ship exits Cyteen System with Shepherd on board. Preparations begin to remove his amp'klie for transplant into his Mirror Universe counterpart.

III.                Low Colonel Ml'Torca contacts Starfleet and notify them of the situation.

IV.               Before receiving a response, the run-about Solarium arrives to pickup the Intel team and possible drop off the new Chief Science Officer.

V.                  F.Adm. Bremer discusses the situation with Ml'Torca via sub-space. Bremer wants the Kep Salu to return to Avalon, and he'll assign another ship to investigate and find Shepherd. Ml'Torca wants to keep the Kep Salu in charge of the investigation. Bremer, after some discussion (possibly heated), Bremer, with reservations, agrees to leave Ml'Torca in charge of the investigation. He sends a ship to rendezvous with the Kep Salu to pick up the Orions (Possibly the USS Laffey) to transport them to a security station. Also, the Diplomatic Mission to Cyteen is suspended for the time being by Bremer, until the return of Commodore Bremer.

VI.               Meanwhile, Marcus wakes up and sees who kidnapped him, himself, and his mirror sister.

VII.             Jess explains to him that they are going to use him as spare parts for Melak, starting with the amp’klie, and if necessary, using other parts as well.

VIII.          Marcus attempts to talk his counterpart and his sister out of it.

IX.               Ml’Torca and crew rendezvous with the other ship, and transfer the Orions.

X.                  At the end of the system, the Kep Salu finds an odd energy signature. After some scans, they find that this signature continues away from the Cyteen system, and back into Federation space. The Kep Salu follows, about 2 days behind.

XI.               It becomes known to the persons in the small fighter that it is leaking some form of energy that makes it trackable. After being looked ninto, it is determined that Eneg Surkei, the Doctor from the Mirror Universe who accompanied Melak (Marcus) and Jess. Before he can explain anything, Jess disentigrates him, which buts her brother into a predicament, since Eneg was the one who was suppose to remove the amp’klie.

XII.             Melak’s condition gets worse, which prompts Jess to stop the fighter,a nd wait for the arrival of the Kep Salu. Somehow, she manages to kidnap Harry, and tells him that if he doesn’t perform the operation, both him and Marcus will die.

XIII.          What I’d like to see is something along the line of Harry uses the genetronic procedure that was used with Worf to make a replica of Marcus’s amp’klie, and then surgically inserts it into Melak, thereby allowing both to live.

XIV.          After the surgery, both Marcus and Harry are returned to the Kep Salu, and the fighter escapes into the Mirror Universe.

XV.            Commodore Shepherd, after being certified to return to duty, returns to Cyteen to complete the diplomatic mission, which is successfully completed.

XVI.          A few days later, as the Kep Salu returns to Avalon Fleet Yards.

XVII.       Jess appears, from the Mirror Universe, and tells Marcus that Melak is recovering quite well. She thanks him, kisses him on the cheek, and returns using a converted transporter to her own universe.

XVIII.     Marcus returns to the Tomar and readies it for the next mission.