Oh, the 'Keepers of the Lost Cities' series is such a fun ride! I binged it last summer, and the order is super important because the plot twists build on each other. Here's the sequence: 'Keeper of the Lost Cities' (obviously the first), followed by 'Exile,' 'Everblaze,' 'Neverseen,' 'Lodestar,' 'Nightfall,' 'Flashback,' 'Legacy,' and finally 'Unlocked.' The last book, 'Unlocked,' is a hybrid—part story, part lore compendium.
I love how Shannon Messenger crafts this world—each book peels back another layer of Sophie's abilities and the hidden conflicts in the elven society. The character growth is phenomenal, especially Keefe's arc. If you're new to the series, avoid spoilers like the plague! The mid-series reveals in 'Neverseen' and 'Lodestar' still live rent-free in my head.