Long-time resident Angus McPherron has a very special birthday coming up--his 100th! Known as the "old man of the sea" by Sea Harbor residents, he's lived in town all his long life and has shared plenty of colorful tales of the area.

Back in town to fill a much-needed nursing position at the free clinic, Charlie Chambers, Izzy Perry's brother, is staying in one of the handful of cottages Angus owns. The yarn shop owner is thrilled he's in town--though she'd like to know more about his mysterious roommate, Annie Smith. Still, she's grateful that each morning Charlie checks Angus's vitals and makes sure he takes his meds.

Meanwhile, Izzy and the other Seaside Knitters are busy planning Angus's birthday bash, knitting his beloved gulls into everything they make. With bands rehearsing and the menu set, Angus's celebration promises to be unforgettable. But the day before, when Charlie stops by Angus's cottage, he finds the old man has died in his sleep. Shocked and saddened, the town decides to go ahead with the festivities, which will now become a celebration of the old man's life.

But when Angus's closest friend, Father Northcutt, is found on the floor of Angus's cottage, unconscious from a deadly blow to his head, Angus's death is examined more closely, and soon is a suspected homicide. As the knitters delve into Angus's history, more questions than answers surface. Soon the whole community is concerned over what now looks like murder, a tragedy buried deep in a shameful chapter in Sea Harbor's past. And one that may point to a killer still in their midst . . .