"Happy Birthday, darling girl." Ever since she can remember, Roisin has received a birthday card in the post. Signed with love from the birth mother she has never met. Brought up by her adoptive parents, Keeley and Doug, Roisin has wanted for nothing. But on her thirtieth birthday a letter comes that shakes her world. For Keeley, who's raised Roisin as her own, the letter reminds her of a secret she's been holding for thirty years. And for Nell, keeping watch in the lighthouse, the past is a place she rarely goes. Until a young runaway arrives seeking shelter, and unwraps the gift of hope for them all.