Sergeant Valeriya Oretsev - or just Val - had tracked Bo Yul-Bayur all the way to the (very frustrating) shootout between Shu and Fjerda that ended in his death and the capture of his daughter, Kuwei Kir-Bo, by Fjerdan witch-hunters.

Val isn't well suited to breaking into Shu research facilities, so if the Darkling wants to get her hands on jurda parem that way, she's going to have to send someone else. 

But she is exceptionally well suited to pursuing the witch-hunters up the coast - 

She isn't fast enough, though, and they get Kuwei Kir-Bo behind the unbroken walls of the Ice Court before she can do more than take down a few witch-hunters. (Assholes.) They didn't get a good look at her face, at least, which means a short run and a quick change of clothes lets her blend into the city, where she tracks down one of Ravka's spies (giving the appropriate code words, and also advice on being less embarrassingly easy to track) and then cools her heels until the Darkling can figure out a way to get a team into the fucking Ice Court. Or until she just calls Val back, but Val's got a hunch that she's not about to let Kuwei slip through her fingers. 

Confirmation of that hunch comes in the form of Sturmhund, legendary pirate - unofficial Ravkan privateer, which is the extent of her identity that Val has clearance for - who's somehow swanned her way into an invitation to Hringkalla, the massive spring festival. Val's swept into her 'entourage' - not the Ravkan diplomatic team, who probably at best will be able to provide extraction backup in case of catastrophic failure to sneak away, with how closely they're being watched - and that somehow gets them all the way to White Island (Val is seriously impressed), where Val quietly scopes out the crowd while Sturmhund draws attention (apparently via vying for an 'audience' with the Crown Princess, which, good luck to her) - 

And then she sees Kaz Brekker, of all people. 

Well, they knew they wouldn't be the only ones after Kuwei - the Dregs' presence just means their competition is actually serious - 

At which point she follows Kaz's gaze to a building ruckus at the center of the court, near the throne -