_The Thermopylae Protocol_ by David Weber and Jacob Halo

This is the 6th title of a time-traveling series. In the first book
(_The Gordian Protocol_), Raibert Kaminski and his AI companion,
Philosophus, while crewing the Transtemporal Vehicle (TTV) Kleio,
discovered a serious problem. In the process of solving that problem,
they recruited a goodly number of people, who became founding members of
the Gordian Division (i.e., the time police) of a circa 3000CE
civilization�s (Sys-Gov) police force (Sys-Pol).

While arguably the founder of the Gordian Division, Raibert is not the
division head, he is the leader of Team Kleio, which gets the difficult
and weird jobs. Thus, when the cargo ship that contained the first batch
of equipment for the Dyson Project (a mega-engineering job that was
going to convert the planet Mercury into lots and lots of solar electric
panels) blows up and the investigation found temporal anomalies, Team
Kleio is sent to aid the investigation. They discovered that somebody
was playing dangerous games with time (in particular, a Gordian Protocol
violation - i.e., splitting a time line, killing many people is the
easiest, though saving the lives of many people also works).

They report this in person to the head of the Gordian Division, who was
attending a meeting at the Providence Station, a joint Sys-Gov/Admin
research station in the Transverse (the �space� between the time lines -
Admin is the system government in another time traveling timeline).
After that, Gordian Division TTVs are sent out to search for the doubled
timeline. That meeting had a bit heated because somebody was providing
Sys-Gov technology (generally more advanced that what Admin has) to
various terrorist groups in Admin. The heat gets much hotter when the
Directory-General of Admin�s Department of Temporal Investigation (DTI)
is blown up by a bomb while walking down a passageway in Providence
Station. News of this arrive at the desk of the Director-General�s
designated acting successor, Jonas Shigeki, who is DTI�s liaison with
Sys-Pol and is stationed at the Sys-Pol headquarters station in Earth
orbit.

Coincidentally, Isaac Cho (of Sys-Pol�s Themis Division) and Susan
Cantrell (of DTI) were at the headquarters being debriefed on the
exchange program that had Susan seconded to Isaac the last 6 months.
Jonas takes advantage of this and requisitions them to be the lead
investigators.

 Isaac and Susan start the investigation at Providence. They find a
murky trail (and reason to believe that somebody knows too much about
Sys-Pol procedures). Since they believe that this was connected to
covert support of terrorists in the Admin timeline, they look into a
couple of incidents there. Meanwhile, Team Kleio encounters an unknown
TTV and finds some clues in the wreckage (including a reference to a
Phoenix Institute) and after some educated guess work, finds the doubled
timeline (but which branch was the new one?). After Team Kleio and Issac
and Susan return to Providence Station, they pool their findings and
come to some conclusions. Raibert leads a joint Gordian Division-DTI
task force to where they believe the Phoenix Institute has set up
operations. They arrive just in time for the launch of Phoenix�s �Death
Star� - nothing short of most of the time travel machines controlled by
Gordian Division and DTI can stand up to it, nothing that the Amin has
can stand up to it - �Death to the despotic Admin regime and its
supporters, Death, Death!� (the previous is not an actual quote, but is
a dramatization).

Most of DTI�s armed time machines (BTW, these vehicles are not small)
are gathered close to the Admin timeline �location� in the Transverse
with a few Gordian division time machines as well (most of the Gordian
Division time machines have not yet returned from their searches of a
doubled timeline). The combined fleet nibbles away at the �Death Star�,
but even with a fortuitous destruction of its time travel drive, it
still reaches the Admin timeline and starts to deploy its payload
(because it took so much damage most of the payload was destroyed before
reaching their targets). At this point, Admin receives entirely
unexpected help that held off Phoenix�s attack long enough for a Sys-Pol
relief force to stamp out the infestation.

As for the wrap up, the guilty are punished, the (surviving) virtruous
are rewarded (perhaps a bit too much so, I have some doubts). I have not
heard on whether there will be a seventh title in this series (this book
has could be viewed as a wrap-up), however, IIRC, Jacob Holo had
mentioned that he had outlines for more stories.

--
"We have advanced to new and surprising levels of bafflement."
Imperial Auditor Miles Vorkosigan describes progress in _Komarr_.
�-----------------------------------------------------
Robert Woodward robertaw@drizzle.com