(2018) Prepare to enter the secret world of the ninja. In this manual, you ll learn all you need to know about ninja spy techniques as well as the stealth training needed to undertake secret missions. You ll also learn how to use two ninja spy essentials: the UV secret-message pen and the ninja headband, both included with your manual. Finally, at the back, you ll find pages to plan your secret missions, solutions to the training exercises and a chart to record the progress of your ninja journey and goals.