From the back cover:
Follow the Path of Waves and forge your destinies as Rōnin in the Emerald Empire
The path of waves is never an easy one, as the rōnin who journey across Rokugan discover. The small, sleepy community of Twin Blessings Village holds dangerous supernatural mysteries, and the nearby woods and roads are filled with threats that could imperil travelers. Even within the safety of castles lurk hungry enemies with hidden guises and deadly motivations.
A supplemental set of encounters for the Sins of Regret, Cresting Waves expands upon that adventure with three tales that can be used to add depth and new intrigues as the PCs adventure as lordless samurai. These new encounters can also be used for other adventures for the Legend of the Five Rings Roleplaying Game in which the PCs are gaijin or even peasants striving to forge their own path. Lastly, Cresting Waves includes GM guidance for rōnin PCs who rise to power and become rulers of their own castles!