A dark sky park where even the slightest glimmer of light is blocked out provides a fascinating backdrop for Chicago writer Lori Rader-Day’s inventive fourth novel “Under a Dark Sky” (Morrow, $26.99).

Mired in grief since her husband Bix died nine months ago, Eden Wallace decides to keep a reservation at Straits Point International Dark Sky Park in Michigan. Bix had planned the park visit as a surprise for their anniversary, and she has just found the reservation while cleaning out a drawer.

It’s an unusual gift because Eden’s fear of the dark is pathological, but she hopes the visit will give her a new perspective on her life and get her away from her Chicago home.

Instead of solitude, Eden finds herself sharing the resort with six strangers — college friends who booked the cottage for a reunion. She stays anyway because has been doing a lot of hiding lately, avoiding people and alienating friends tired of hearing about Bix’s death. Besides, the park won’t refund Bix’s payment.

The friends make Eden uncomfortable, but she’s drawn in by their personalities and their complex relationships. Despite their shared history, the group has an odd dynamic.

“These people didn’t even seem to know how to enjoy one another’s company,” Eden observes.

Complicated jealousies and devastating secrets are revealed when one of the six is murdered.

Rader-Day expertly plots an ingenious mystery in “Under a Dark Sky.”

"Under a Dark Sky" by Chicago novelist Lori Rader-Day.

Click here to read first two chapters of “Under a Dark Sky” by Chicago novelist Lori Rader-Day. | William Morrow