Twenty years after its launch and disappearance,
the spaceship Medusa is drifts back into Dellah space, and an expedition
is prepared to find out what went wrong. One of the expedition members,
Maryanne Decleiter, dies in a mysterious accident at the Advanced Research
Department, and the head of the project team, Taffeta Graize, invites Benny
to join the expedition in her place. Benny is suspicious of Graize's motives,
as is Decleiter's friend Commander Skutloid, who privately tells Benny
that she and Decleiter had a lot in common. Benny and Skutloid enlist Irving
Braxiatel's help, and he digs up information on the Medusa's launch
and gives a datacube to Benny to peruse later. Medusa was entirely
remote-controlled from Dellah; the purpose of the project, conducted in
the final days of the war between humanity and a race of exterminating
aliens, was to launch a new class of remote-controlled luxury space liners
to bring enjoyment back to space travel again.
Before the expedition sets off Benny undergoes a medical
examination, including an injection to protect her against any lingering
viruses on board the Medusa; she's told to abstain from alcohol
to avoid side-effects, but quickly forgets the warning. When she's introduced
to her fellow expedition members she finds it surprisingly easy to categorise
their personality quirks into quick pigeonholes. The expedition sets off
to the Medusa, where things go wrong almost immediately; all of
their equipment shuts down, and a stranger named Stuart Stonely shows up,
claiming to have been sent on ahead to get the Medusa ready for
their arrival. The expedition soon finds the former crew and passengers'
bodies, and realize that they've all been murdered.
As the first few days pass, the expedition members begin
to experience intermittent hallucinations, seeing the Medusa fully
functional, just as it was twenty years ago. Benny and Stuart slowly begin
to realize that the expedition members are slipping into the behavioural
patterns of the former crew, and that history is beginning to repeat itself.
Even Benny is beginning to unconsciously adapt to some of the traits of
a former passenger. While Stuart is exploring the bowels of the ship, Captain
Chromsky finds and attacks him for no apparent reason, and Stuart accidentally
kills Chromsky in self-defense. Benny, meanwhile, has the strangest vision
of all, seeing something humanoid burst out of a shattered pillar in the
ballroom in a spray of amniotic fluid.
For some reason Benny finds it easier to think when she's
had something alcoholic to drink, and eventually she remembers Braxiatel's
datacube and discovers that it's still functioning. She and Stuart discover
that, during the launch of the Medusa, Jackson Hart -- one of the
research team who designed the Medusa, accused and convicted of
killing all the others on his team -- escaped from custody and stowed away
on board. As Benny ponders what she has learned, she accidentally discovers
that two expedition members are having an affair, and, desperate to keep
their affair a secret, they drug her and seal her in an airtight cabinet
in the medical bay -- which is exactly what happened to Benny's counterpart
on the original passenger manifest. This time, however, Stuart is there
to save her, and after surviving beyond her counterpart's death she finds
the intrusive personality traits are no longer present in her mind.
The expedition members lose all sense of their former
identities and take on the roles of the former crew and passengers, and
when they find Stuart they accuse him of stowing away and murdering Chromsky
and nearly beat him to death; Benny saves him, but discovers that this
is exactly how Jackson Hart died. The rest of the expedition members murder
each other when the jealous Andrea discovers her co-workers' affair and
kills them both, triggering a gunfight which ends with everyone dead, including
her. Again, this is exactly what happened to the previous expedition. But
this time, Stuart and Benny have survived.
Benny finally confronts Stuart about his true identity,
having guessed that he made up his name on the spur of the moment after
seeing a door marked "Stewards Only". Stuart admits that he doesn't really
know who he is; his first memory is of awakening aboard the Medusa
twenty years ago, and for some reason the memories of the other expedition
members are all jumbled up with his as well. Now that the experiment is
over, however, a hologram of Taffeta Graize appears and explains the truth
to them; a select group of individuals with sharply defined personality
traits were selected and drugged in order to create a composite mental
entity. Graize accepted military funding and turned the original project
towards the creation of a race of super-soldiers, and arranged for the
rest of the project team to be murdered when they discovered the truth;
Hart was blamed for the murders but escaped and stowed away on board the
Medusa, only to become part of the process himself.
Stuart realizes that he's the first of the breed, who
awoke prematurely; the team sent to dissect him underestimated his strength,
and he killed them in self-defense and smashed Medusa's navigation
and communications systems in a blind panic before fully achieving self-awareness.
This is why Medusa was lost and diverged from its course. When it
was detected again, Graize organized a follow-up expedition with the same
basic personality traits; the "inoculations" in the team's medicals were
meant to smooth over any differences between their own personalities and
their counterparts'. Benny's didn't take properly because it was a rush
job to replace Decleiter's, who was murdered when she got too close to
the truth; also because Benny's alcohol habit interfered with the drugs
she'd been given. But now the expedition has achieved its purpose; the
other genetically engineered soldiers are awakening, their first impulse
to kill. Graize sends the ARD's head of security, Kirk, to lead the soldiers
on their first test run -- the murder of Benny and Stuart.
