take2.js

 return Promise.try(function () {
     //return fs.readFileAsync(status.filename, 'utf8');
      return MongoClient.connectAsync(MONGODB_CONNECTION_STRING).then(function(db){
              var results = null;
              return Promise.try(function(){
                  return db.collection("downloads").findOneAsync({key: status.filename});
              }).then(function(item){
                  results = item;
                  return db.closeAsync();
              }).then(function(){
                  return results;
              });
          });
  }).then(function(content) {
     // ... 
     
  });