Related Clues:

• It's good when airtight
• Underlying idea
• Make a deduction
• Tot's frequent question
• Suspect's concern
• Proof of innocence
• "I was away on business," e.g.
• Wrongdoer's excuse
• Save the Whales, for one
• Out, at the police station
• Free Tibet, e.g.
• Excuse of a sort
• Crime story?
• "Give me a reason"
• Defendant's testimony, maybe