There are 2 books in the Nightlights series. The newest book is Hicotea which came out in 2019.

1
Nightlights

Book cover of Nightlights
Every night, tiny stars appear out of the darkness in Sandy's bedroom.
Sandy catches them and creates wonderful creatures to play with until she falls asleep, and in the morning brings them back to life in the whimsical drawings that cover her room. One day, a mysterious pale girl called…
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2
Hicotea

Book cover of Hicotea
In this mesmerising follow-up to Nightlights, Lorena Alvarez explores our relationship with nature and animals.

On a school field trip to the river, Sandy wanders away from her classmates and discovers an empty turtle shell. Peeking through the dark hole, she suddenly finds herself within a magical new dimension. Filled…