Attack of the plants

"Next stop...The Magic School Bus heads to the Galapagos Islands to learn about invasive species! Seat belts everyone! The class returns from summer break to find their beloved Ms. Frizzle has been promoted and her younger sister Fiona Frizzle is taking her place. But Arnold is worried. What if the new Ms. Frizzle makes a mess of things? His fears come true when she takes them on a field trip and everything goes wrong! Can Arnold find a way to make it right again?"--Dust jacket flap.