More like three and a half, but not quite a four for me.
It was an ordinary day for Morgan until her high school was kidnapped by aliens! Except Morgan wasn't exactly ordinary with a father who was a hardcore prepper starting the day with a fire alarm. Morgan had stopped buying into her father's paranoia until she landed on another world, and suddenly needed that knowledge.
Morgan turned out to be smart, brave, and resourceful. She did what was necessary, even when the other kids ignored her advice, and goofed off. The kids being disorganized, and wasteful, seemed realistic to me, though not exactly pleasant to read through.
Most of the book was an adventure that moved quickly. There were some fun surprises, and I liked the direction the story took. It ended at a logical stopping point, not exactly a cliffhanger, but with plenty of story left to tell.