Related Clues:

• Really must
• It's not optional
• Has no alternative
• It's required
• ___-win situation
• Be compelled to
• Essential thing
• Something vital
• Needs to
• Can't-miss event
• Is obligated to
• "It's a __-see!": "Don't miss it!"
• It's not an option
• Non-negotiable
• Event not to be missed