50 books • 4 series
Book #1: La octava hermana
Book #1: The Eighth Sister
Book #2: The Last Agent
Book #2: Espías en fuga
Book #3: The Silent Sisters
Book #2: Beyond Reasonable Doubt
Book #1: My Sister's Grave
Book #1: La tumba de Sarah
Book #2: Her Final Breath
Book #2: Su último suspiro
Book #3: In The Clearing