Unicorn Quest, start of the series.

Unicorn quest is the first book of the series about two girls named Claire and Sophie.

In this series, two ordinary girls find a fireplace that leads to another world. They find that the other world is magical. The world used to have unicorns that went extinct except for one when hunters tried to kill Unicorns to use their body parts for magical items.

Now, Claire and Sophie, have the job to find the last Unicorn. While trying to find the last Unicorn, Claire and Sophie find out that the queen, who everyone thought was saving Unicorns, was actually the one killing them. Claire and Sophie were able to save the unicorn in the end.