Related Clues:

• In installments
• Kind of number
• Soap, e.g.
• One thing after another
• It's a long story
• Type of number
• 'Soap,' for one
• Ongoing story
• Story that's 'to be continued'
• Soap opera, e.g.
• "Flash Gordon," e.g.
• 'Buck Rogers,' for one
• Soap opera
• Published in installments
• See 66-Across