Red Lobster used to be one of the biggest names in the world of casual dining — but now the restaurant chain is on the brink of collapse as it files for bankruptcy protection. Was its famous "endless shrimp" promotion really too much for the restaurant to handle? Or is this more about the business decisions of a private equity firm and a major Thai seafood company?

Business Insider senior correspondent Emily Stewart takes us through the story of Red Lobster's years-long fall from glory — and how it joins a club of other businesses knocked out by private equity.