2019’s The River South is the second volume of Marta Randall’s Riders Guild series.
Abandoned by her mother, Kieve Rider, as a baby, Shrug was left to the care of the Rider Guild in Koerstadt. The Guild was a careless guardian and Shrug a challenging ward.
Someone else seems to have a keen interest in Shrug’s future. This unknown party would like Shrug’s future to be short. Shrug escapes the first assassin.
One of the riders, Daenet, remembers Kieve fondly and tries to protect her daughter against further attempts. He takes Shrug with him on a river voyage, which gets the girl out of Koerstadt. Daenet is accompanying Lord Kyst, whom he serves as rider (and who is also his lover).