When last we left Fitz (at the end of Assassin's Apprentice), Fitz had thwarted a plot against Prince Verity, the King-In-Waiting for the Kingdom of the Six Duchies. However, the ringleader of the scheme, Verity's younger brother Prince Regal, remained in his position. The Red Raiders still threaten the shores of the kingdom, and Verity tries to marshal the strength of the kingdom to fend them off. Regal still plots & schemes, and it seems he will do anything.

Two-thirds of Royal Assassin is a very very slow build with Verity and Regal slowly moving pieces on the board, all seen from Fitz' perspective. He knows very little of what goes on, so it seems even slower.

The side plot is Fitz courting his beloved Molly, a servant woman he has known since childhood. King Shrewd forbids Fitz from marrying Molly; he wishes for Fitz to marry the daughter of a noble to cement a royal alliance. Over time, Molly gets madder & madder, not understanding why Fitz won't run away with her to live anonymously in the countryside.

Everything interesting happens in the last third of the book. And the book is long. And, as it is book two of a trilogy, ends somewhat on a cliff-hanger. Much of the plot of Royal Assassin is wrapped up, but many many threads are left dangling for the final book of the series.