Professor Waning Glory takes his new friend Tubby on a trip in a boat that stays always at 9 p.m. in a lofty time-river of some sort, starting at Coney Island, then Chicago, then Denver, and farther west. The professor is able to briefly stop the boat above Chicago, where time for those below stays frozen at 9 p.m., and when their boat crosses the 180° meridian, they travel back a day. Eventually, they arrive back at their starting point on Coney Island, where it is still 9 p.m.

After sailing around the world, the Queen of the Sea returns to port without a sole aboard, and only private investigator Dolan knows why.

Mark is living an endlessly time-looping day of skipping summer school to, um, let’s call it “requisition” a front loader, do little acts of kindness around town, and annoy his younger sister when he’s unexpectedly interrupted by Margaret who’s careening her way through the same day while nobody else around them realizes what’s going on.

<spoiler!>One reviewer suggested that the story would have been better told from Margaret’s point of view. Certainly she has an interesting story of her own—one of loss so intense that it stops her world and kidnaps Mark. And yet, for me, Mark’s story is both compelling and well told, and I’m glad the author told his story. He is sensitive and lost and looking for his way in an upended world. He’s not particularly aware of how others feel, but maybe he’s getting there, and somehow Margaret grounds him and provides room to grow to the point where he can offer unconditional friendship to her (and to others) exactly when it’s needed. Is that a corny, uplifting story about tiny, perfect hypercubes that were meant to be? Yes, enjoyably so. I also enjoyed the nods to other popular-culture time travel escapades, though not so much the handwaving attempt at grounding things in science with Mark’s algebra teacher.</spoiler!> Sorry. Sometimes I feel a compulsion to drop into critic mode myself.