The Babylonian exile does not last forever.  Likewise, anytime we feel that we are far from God’s love and mercy, we are reminded that no exile lasts forever.  There is a time to return!
Of course returning is not an easy thing and many of God’s people never return.  They stay in Babylon.  A few, a remnant never leave Jerusalem and the surrounding area.  Ezra and Nehemiah is the story of those who were in exile yet returned to rebuild Jerusalem.  In Hebrew scriptures, they are originally one scroll, not two distinct books. 
The beginning is rebuilding the temple.  It happens by decree of King Cyrus of Persia.  But it is a hard work and even after the Temple is rebuilt, the city is not.  So Nehemiah tells the story of rebuilding the walls of Jerusalem.  It is clear that almost everything was destroyed before the exile and the process of rebuilding was long and difficult.  The exile itself changed the history of Judaism. The Temple was the center for religious life in Judaism but after it is destroyed and God’s people are scattered, they had to struggle with how to be faithful. It is during this time that the Torah – the first five books of the Bible – become so central.  It is necessary to record and to share their faith through writing for the first time. For Christians and modern Jews, our faith is still based and centered on scripture, not on location.  
I thought it might be helpful to share some dates to help you put things into perspective.  The first temple was built by Solomon sometime in the 10th century BCE (Before Common Era). Most likely completed near 966 BCE.  This temple was destroyed by the Babylonians in 586 BCE.  Then the exile to Babylon took place.  Babylon was overthrown by Persia.  From 520 to 516 BCE, the new temple was built.  
The whole story is a great reminder that God does remain faithful and God’s people are not forgotten.  You too are never forgotten by your Creator and Redeemer!  Rejoice.