|Book(s)|| A Storm of Swords (mentioned)|
A Feast for Crows (mentioned)
Appearance & Character
A Storm of Swords
Harwyn and his brothers Ser Dennis and Ser Peter Plumm are among the men who are sent by Lord Tywin Lannister to the Riverlands in search of his son, after Ser Jaime Lannister has been released from Riverrun by Lady Catelyn Stark.
A Feast for Crows
Harwyn considers the tales that Lord Beric Dondarrion can't be killed lies. He promises Lady Amerei, whose father Merrett Frey was hanged by the Brotherhood Without Banners, that he is going to bring her Dondarrion's head. He believes that the smallfolk in the Riverlands secretly hide and support the Brotherhood, lying about this to their lords.
Upon hearing reports that there are outlaws on the other side of the Trident, he takes five knights and twenty archers and goes searching for them, making him miss Ser Jaime Lannister's visit to the castle when Jaime is on his way to ending the siege at Riverrun. When he learns about Harwyn's vow to Lady Amerei, Jaime reflects how very different Harwyn is from his more companionable brothers, and, noticing her blushing when she calls Harwyn gallant, he suspects that "Gatehouse Ami" does have an amorous interest in Harwyn. When Jaime warns Lancel about this, his cousin expresses his indifference, announcing that he is going to renounce lordship and marriage and that Harwyn can have both, if he wants to.