The Vermilion Emporium by Jamie Pacton

Two teens discover the secrets of a magical curiosity shop in a story of timeless love and deadly consequences.
The heart-wrenching story of The Radium Girls meets the enchanting world of Howl's Moving Castle. Perfect for fans of The Starless Sea and Divine Rivals!
"[A] hauntingly romantic fantasy adventure." -Publishers Weekly, Starred Review
It was a day for finding things...
On the morning Twain, a lonely boy with a knack for danger, discovers a strand of starlight on the cliffs outside of Severon, a mysterious curiosity shop appears in town. Meanwhile, Quinta, the ordinary daughter of an extraordinary circus performer, chases rumors of the shop, the Vermilion Emporium, desperate for a way to live up to her mother's magical legacy.
When Quinta meets Twain outside of the Emporium, two things happen: One, Quinta is sure she's infatuated with this starlight boy, who uses his charm to hide his scars. Two, they enter the store and discover a book that teaches them how to weave starlight into lace.
Soon, their lace catches the eye of the Casorina, the ruler of Severon. She commissions Quinta and Twain to make her a starlight dress and will reward them handsomely enough to make their dreams come true. However, they can't sew a dress without more material, and the secret to starlight's origins has been lost for decades. As Quinta and Twain search the Emporium for answers, though, they discover the secret might not have actually been lost-but destroyed. And likely, for good reason.
A powerful and romantic adventure set in a whimsically magical world. The Vermilion Emporium shines a light into the darkest spaces. It's about healing in a world shrouded with despair and discovering a spark of magic when you need it most.