Download or read book The Unspeakable Unknown written by Eliot Sappingfield and published by G.P. Putnam's Sons Books for Young Readers. This book was released on 2019 with total page 354 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thirteen-year-old Nikola Kross's father, who was kidnapped by extraterrestrials, is still missing and it is up to Nikola and her new friends at the secret boarding school for scientific geniuses to rescue him in this sequel to "A Problematic Paradox."