Benioff, David. City of Thieves.

In this coming-of-age story set during the siege of Leningrad, Lev and Kolya, a teenager and a young soldier who have both been arrested for petty crimes and sentenced to death, are given one last chance by a Colonel to save their lives if they can achieve the impossible: find a dozen eggs for his daughter's wedding cake. The next few days Lev and Kolya go on an epic journey to find this rare ingredient, navigating the terrors and sadness of their desperate city.  After crossing into German territory, Lev and Kolya must depend on each other more and more and their unlikely friendship strengthens as their mission reaches new levels of danger and consequences.

The modern-day odyssey is based on the experiences of the author's own grandfather, a now-retired Lev, who lives in Florida. Although set within a period of a few days, the events that happened effect the teenager for the rest of his life. This story should not be missed.