I haven't seen the series myself, but apparently Vance's character will facilitate a big reveal that was teased in the series premiere.
Vance’s character factors into the aftermath of the beach murder. He’s been tapped for four episodes and will play a loyal employee of Conrad (Henry Czerny) and Victoria Grayson (Madeleine Stowe), and is described as someone 'who gets caught up in a public scandal and romantic entanglement that Emily will leverage to further her agenda against Conrad and Victoria.' Where most see a new face around Southampton, the devilish Emily clearly sees a new target.
Vance is set to guest star in four episodes, beginning with episode 16 in mid-February.