The Shadow Rule - The Stars and Green Magics, #2

THE ENEMY BY MY SIDE. THE ENEMY IN MY HEART. Ari will never be the Heir again. Her younger sister, Dressa, was supposed to hold her place, but now Dressa's stolen her future rulership. Banished to a resort world to recover from her illness, Ari's determined to reclaim her shapeshifting abilities and race back to the capital. But a young gardener with a mysterious past is taking too much interest in Ari's new persona, and a possessive duke is bent on capturing her attention for himself. Are they both after her heart, or something far more sinister? Dressa won her freedom, won her bride-and won a kingdom she didn't want.
Now, with an alien crisis brewing, she has to step up as the Heir, and maybe, soon, as the ruler. Because there's a secret at the heart of the kingdom. A secret that spans her father's entire rule and could bring everything tumbling down. And she's already let the enemy into her palace, and into her heart. When no one is who they seem and every smile is a weapon, the Truthspoken must find their way to truth before the kingdom crumbles around them. The Shadow Rule collects episodes 37-93 of The Stars and Green Magics, previously published in serial form. Note: This book has main characters who use gender neutral pronouns (they/them/their, fae/faer/faerself).