Wren to the Rescue is a great read! It keeps you hooked and after you read it, you'll run to find the sequels! I just finished reading it for the second time, and it was just as good as I remembered it.
Wren, an orphan at Three Groves Orphanage, finds out that her friend Tess is really a long lost princess, hidden there because the wicked king Andreus wants to kidnap her. Wren is invited to come back to the palace in Cantirmoor with her friend. Unfortunately, the day after they arrive, Andreus strikes and Tess is spirited off to his stronghold in Senna Lirwan. Wren, being the spunky girl that she is, is not content to sit back and watch everyone else search. She uses a magic spell she saw to transport herself to the magic school, and from there decides to run off with a young magic prentice, Tyron, to rescue Tess.
They decide to find the mysterious mage Idres Rhiscarlan, to see if she will help them. When she refuses, they set out on their own to try to prevent the coming war. After a while, they are joined by Connor, Tyron's friend and a prince. After many adventures, involving warrie beasts, secret passages, bridges, armies, thieves and chraucans, they make it into Senna Lirwan.
Wren drinks from a poisoned stream and Andreus tries to take her, but Idres somehow pops back into the stream and saves her, turning Wren into a dog in the process! Poor Wren! But it doesn't seem to bother her all that much, though she is in danger of being a dog forever.
However, more problems soon come their way. Connor has a terrible secret, Wren's friends are captured, and she must find a way to rescue them alone AND get Tess out, before she becomes a dog for good! How does she do it? Read the book to find out!