The Oceans Between Stars, by Kevin Emerson, for Timeslip Tuesday

The Oceans Between Stars, by Kevin Emerson (Walden, middle grade, Feb 2017), is the sequel to Last Day on Mars, an action-packed story of the sun going supernova as two kids, Liam and Phoebe, find themselves scrambling against sabotage and disaster to get themselves and their parents off Mars before it is toast.  This is what happens to them out in space, as they try to rendezvous with the rest of humanity, hoping their little space yacht and the robot piloting it will get them to safety.  Both sets of parents are badly injured, and must stay in stasis, so there's no help from them.  Space is cold and vast and lonely when you aren't sure if you'll ever have a home, and there's the looming fear that whoever the aliens are who are setting suns on supernova fire are going to keep up their nasty work, and no where will be safe.

There's enough plot in just that part of the story for a whole book.  But wait, there's more.

This is not a spoiler because it's how the book starts.

It turns out that the planet chosen for humanity's new home already had sentient beings on it, and all but a few were killed when humanity sent a cleansing inferno down to wipe all life from its surface so that humanity could have a clean slate.  They might not have known for sure what they were doing, but quite possibly suspected....and the 238 survivors want their planet back, and have no pity to spare for humanity's need for a new home.

That's a lot of plot too.  But there's still more.

Phoebe has been keeping a secret.  A terrible one.  She's been secretly leaving stasis to alter the course of their little spacecraft so that it won't reach the rendezvous point when it's supposed to.  Is she still Liam's friend? Her parents' daughter?  Readers of the first book know that she is one of the survivors of the blasted planet, but Liam doesn't, and when he finds out there is great emotional tension and powerful considerations of friendship and loyalty.

And on top of that, you also get time slipping with alien technology! 

[apologies for the next paragraph.  I didn't really understand what was happening with regard to the time travel, and had a choice--I could slow down, and carefully try to make sense of things, or simply keep turning the pages to see what happened next.  I chose the later.  I always choose the later.]

Back on Mars, Liam found an alien corpse, and took from it a device that messes with time, showing him the future or the past, and himself and others doing things in both that have a huge impact on the choices he makes.  He doesn't actually travel through time in a standard boy going to another time way; it's more like time is traveling weirdly around him, or he's traveling within time, or something.  When he encounters the alien whose device it was in a past pocket of time, they try to explain...and neither Liam or I really understood.  But both of us continued on with the story, trusting that events would unravel into some sort of temporal coherence.  Which they did, to a point, although that point involved an increase in the travelling part of the time slipping....and no answers to anything......

So we must wait for the third book....which will involve reading books 1 and 2 again just before it comes out, so that everything makes more sense in my mind.  Good thing the books are worth it!

Kirkus nails it on this one-- "Thrills, violence, time/space questions, and some contemplation about colonization make for action on the thoughtful side"  (To which I will add that this is the sort of book that makes me realize again how much easier it is for me to enjoy middle grade books, with kids as the central protagonists, than it is for me to enjoy YA books these days...there's a clarity of focus to middle grade (or something) that just holds my interest more).