Kevin Costner mortgaged his home and put $38 million of his own money into 'Horizon.' Box-office numbers suggest this was a terrible idea.

• Kevin Costner's "Horizon" was a bust at the box office, making only $11 million in its first weekend.
• Costner invested over $38 million in the movie and paid for its marketing himself. 
• "Yellowstone" fans may not have been enough to help "Horizon" beat out other big draws in theaters.

Kevin Costner is the latest star to be reminded that passion projects don't always yield big box-office returns.