During a journey as haphazard as it is harrowing, Aikins keeps the focus on Omar and the other migrants while giving enough context that we always understand what’s at stake in this high-risk, ever-shifting environment. At times, especially toward the end, the pacing of the book is electrifying. But this is no “Sound of Music” finale. Instead Omar, Aikins and their fellow migrants climb mountains, only to realize they have to go back and find another way. They are apprehended by officials and released, then caught again. At the last minute, a smuggler hustles them onto a boat bound for the very part of Europe they had hoped to avoid, leading to a prolonged period of confinement in one of the worst detention encampments in the European Union. There are no tidy arcs or pat resolutions. Aikins chronicles it all, typing up his notes on his phone nightly, until eventually he has logged more than 60,000 words.Small vignettes tell a larger story. A Greek man yells at the Afghan migrants for swimming in the ocean, then apologizes: “Tell them it’s nothing personal. … We’re both stuck in the middle of something much bigger than us.” Wealthy nations, Aikins implies, love feel-good moments — holding up signs that say “Refugees welcome here!” or awarding humanitarian prizes — but are less interested in the hard work of studying the underlying causes of mass migration from war-torn and economically ravaged countries. Instead, that work falls too often to individuals or small groups who cannot possibly address the scale of the crisis. The swelling waves of people are barely contained by the border camp where Aikins and Omar get stuck, or in the squats and underground hiding places where they stay along the way: “From this dammed-up pool of the displaced, the West takes measured sips.”Aikins does not just criticize governments; he examines his biases in a way that invites readers to scrutinize their own. He finds Omar’s almost obsessive feelings for Laila alternately inspiring and frustrating: “There was no logic to love.” Before the trip, he spends months trying to persuade his friend to leave Afghanistan, but Omar lingers, hoping for some word from Laila. Months into their journey, Omar sinks into a depression, listening obsessively to Celine Dion and searching Facebook for mentions of Laila (who isn’t on social media). Aikins feels “a prick of annoyance” at the hours Omar spends staring at his phone: “What kind of protagonist was he?” Aikins had hoped to write about “someone who spoke English and understood Europe, who marched with the activists and made love to volunteers, a real hero.” But Aikins uses this scene, among others, to shine a glaring light on his own unfair expectations; Omar is not a stock character — the revolutionary hero calculated to rally Western sympathy — but his friend, sad and homesick. Aikins ensures that, to the breathless end, we are rooting for Omar and the world he hopes to create for the love of his life.On this journey, Aikins finds love too, though of a different kind. When he cups a child’s head while their boat flails through riotous waves, when he dances with new friends at an unlikely haven in Athens, when he shares a sandwich with a man who is more brother than friend, Aikins moves past his role as journalist. He experiences the kind of equality that politicians, advocates and religious leaders tout but rarely achieve. Aikins wants to believe in some activists’ vision of a world where transformative, systemic, societal change is possible: “To believe felt like falling in love.” Instead, he discovers that this ideal can be found only “in fragments.” He weaves those fragments into a meticulously told story the world needs to hear now more than ever.