Add Surfacing by Mark Magro to your summer reading list. It's a good book for middle school with no language, romance that progresses no farther than a kiss and most violence is against giant bugs and robots. The story is filled with classic sci-fi elements, including the plot twist at the end.
Speaking of plot, the basic premise is similar to City of Ember by Jeanne DuPrau. Global catastrophe has sent scientists underground where they work to rebuild humanity. Balt is bright and has a sense that something isn't right, but only after he meets Zoe and her mysterious past is he compelled to action. Balt's sidekick AI (who only received a head) adds both humor and wit to the daring duo's attempt to reach the surface.
I'm not a fan of the two person, alternating narrator but both viewpoints advance the story rather than rehash the same events from different perspectives. There is enough sense of mystery, intrigue and suspense to keep the reader moving. Published October 2015, this book has yet to be added to Common Sense Media or Accelerated Reader but you can read reviews at Goodreads.