2.5 rounded up to 3. I enjoyed the start of this book, the isolation, the spiral toward possible madness, the mystery of why things were so wrong; then the chance discovery of another person and all that entailed. However it then devolved into some Clive Cussler-esque clash with a disaster flick. I lost the characters at that point. Peter was so self absorbed with his own perceived inadequacies, Penny became a source of dialogue info dumping about physics. Most other female characters were there to be saved or threatened or raped. Peter always had exactly what he needed to prevail, pulling items seemingly out of thin air and suddenly knowing how to do just about everything. Find a 100 foot yacht...of course he can sail it and save the day. Need to salt some fish...Peter just happens to have several buckets of salt in his supplies. Need to threaten to tie someone up...Peter pulls a zip tie out of the inside of his jacket. Penny did the same, suddenly becoming a dab hand with firearms after minimal verbal instruction and working out how to make a semi auto weapon full auto because unbeknownst to everyone else, she once fancied robotics.
The cause of the disaster also seemed rather far fetched to me. A lot of the middle of the book is spent trying to explain it, with Peter and Penny happening to come across one of the scientists who had done the research that caused the event...complete with a fully equipped science research vessel. Everything just seemed too contrived.
I didn't really feel anything for the characters. If things are written well, I will often cry when reading. With this book I spent a lot of time rolling my eyes. Their emotions seemed contrived to move the plot forward. A lot of the dialogue was stilted, the characters had a habit of asking What? all the time and it got annoying. Peter, for all his miraculous knowledge of poetry, survival, fighting, sailing, etc was thick as two short planks when it came to recognising the simplest of emotions, appearing to almost purposefully misunderstand or purposefully not bother to find out the reasons behind someone's actions just so the truth can be revealed later. That feels like lazy writing.
I think this could be improved with a developmental edit and a thorough line edit. There were some errors. If we could be shown more of the emotion, drop the info dumps, tighten up the dialogue, and get rid of the deus ex machina stuff then it would be a lot better read.