Related Clues:

• Nathan Hale, notably
• Bug planter
• Do undercover work
• Plotted plant?
• CIA sort
• Agent 'embedded' in this puzzle's theme answers
• Work under cover, in a way
• Herb or tree
• Invisible ink user
• Bit of flora
• One wearing a wire, perhaps
• Word repeated in Mad magazine's '___ vs. ___'
• Telephoto-lens user, perhaps
• Use binoculars, perhaps
• 'Mission: Impossible' figure