The story of the original Thanksgiving feast is hard to find unless you are looking for it.  When the Pilgrims came to this New World and set up the first settlements, they were faced with conditions we cannot fathom today.  A wilderness overwhelmingly untouched and hostile.  Some natives were friendly while others were not.  

One of the first orders of business was to establish means for sustaining the colonists.  Initially the colony was set up in common and all land was farmed communally.  William Bradford documents the results of this approach in his journal.  He plainly states that men refused to work for the benefit of other men's families. Women and children often complained of ailments that prevented them from helping with community works. This led to starvation and death.

These conditions forced the colonists to make changes.  They created private lots for families to manage.  Almost immediately imagined ailments vanished and men and women alike worked industriously to provide for themselves (and by extension ultimately providing for the colony).

William Bradford documents the change he observed.  

Property: William Bradford, Of Plymouth Plantation

The subsequent harvest bounty helped them celebrate in the fall with plentiful food.  Thanksgiving is a distinctly American holiday.  It is a giving thanks to God for his divine providence, for helping them realize the affront to nature that their early taste of communism was, and for the bountiful feast they could share with their community.