Nightwatch over Windscar - The Weep

Set in the universe of Rory Thorne, the second book in this sci-fi mystery series follows unlikely heroes who must discover the secrets of ancient ruins.

Iari is being hailed as a hero--which she finds annoying. As far as she's concerned, she just did her job as a templar of the Aedis, a multi-species military organization committed to protect the multiverse. But after she helped stop separatists from sabotaging the entire Confederation, Iari has received a lot of unwanted attention.

The attention, at least, provides a reprieve after she's promoted to lead a team to the northern tundra of Windscar. There is a report of recently discovered ancient, subterranean ruins that have mysterious connections to the dangerous arithmancy used by the now-dead wichu separatists.

With her team, Iari brings her friends: Char, a decommissioned battle-mecha and newly-joined templar, and Gaer, ostensible ambassador and talented arithmancer. As they delve the ruins, they find remnants of long-ago battles, bits of broken armor and mechs--which unexpectedly reanimate and attack. But they aren't the only danger, as the inhabitants of Windscar also prove unexpectedly hostile to visitors.