Seaside Knitter Birdie Favazza is thrilled that her granddaughter Gabby will be visiting for the fall and attending the Sea Harbor Community Day School. Gabby loves the school, with its newly-adopted progressive curriculum, and she loves that the Seaside Knitters are teaching knitting as part of the enrichment program. It's a huge success, and on crisp autumn days, girls camp out on the terraces, knitting up hats for charity.

But not everyone is happy with the direction the school is taking. Outspoken board member Blythe Westerland has sparked tempers with her determination to unravel the current administration. Then, on the evening of an elegant school event, Blythe's body is found near the school boathouse.

With a killer on the loose, Birdie is determined to keep Gabby safe. Working together, the Seaside Knitters carefully unravel the layers of Blythe's complicated life, bringing faculty members and town residents under scrutiny. Before the cast-off rows are made on the students' projects, the knitters will need to stitch together the evidence to see if a murderer has been walking beside them all along.