'Arif and Two Sentries

Secret codes, a Sentry goes missing in the masjid, and a Sentry is tempted to cheat. Suspense, STEM and mystery all in one pack!  

Readers join Egypt's best boy detective and test their wits against a cunning thief in The Periodic Thefts, and readers join the Sentries of the Sunnah as they try to help two sentries in trouble.