Under the Cover of Starlight

Zara has a secret-she's an alien. Following her mission to study humans and understand them, Zara, disguised as a human girl, finds herself in a children's hospital where she meets Lila. Thirteen year old Lila spends her time studying science, talking to her pet rat, Snowball, and wheeling herself all over the hospital. She never expected her life to change after meeting Zara, the strange new girl at the hospital.
But when they both discover a mysterious, glowing plant in the garden, everything shifts. Together, the two new friends make scientific discoveries, form unlikely friendships, and face the odds-as well as bullies -that rise against them. But with the weight of Zara's secret and Lila's worsening health pressing on them, will they be strong enough to face it all? And will their discoveries bring them together or tear them apart?