diff --git a/lib/blockchain.js b/lib/blockchain.js
index 6498491b..7cadd778 100644
--- a/lib/blockchain.js
+++ b/lib/blockchain.js
@@ -5,12 +5,16 @@ var $ = bitcore.util.preconditions;
 var _ = bitcore.deps._;
 
 function BlockChain() {
-  this.tip = null;
+  this.tip = '0000000000000000000000000000000000000000000000000000000000000000';
   this.work = {
     '0000000000000000000000000000000000000000000000000000000000000000': 0
   };
-  this.height = {};
-  this.hashByHeight = {};
+  this.height = {
+    '0000000000000000000000000000000000000000000000000000000000000000': -1
+  };
+  this.hashByHeight = {
+    '-1': '0000000000000000000000000000000000000000000000000000000000000000'
+  };
   this.next = {};
   this.prev = {};
 }
@@ -44,7 +48,7 @@ BlockChain.prototype.proposeNewBlock = function(block) {
   $.checkArgument(block instanceof bitcore.Block, 'Argument is not a Block instance');
   var prevHash = bitcore.util.buffer.reverse(block.header.prevHash).toString('hex');
 
-  if (!this.work[prevHash]) {
+  if (_.isUndefined(this.work[prevHash])) {
     throw new Error('No previous data to estimate work');
   }
   this.addData(block);
@@ -118,7 +122,9 @@ BlockChain.prototype.getBlockLocator = function() {
   var currentHeight = this.height[this.tip];
   var exponentialBackOff = 1;
   for (var i = 0; i < 10; i++) {
-    result.push(this.hashByHeight[currentHeight--]);
+    if (currentHeight >= 0) {
+      result.push(this.hashByHeight[currentHeight--]);
+    }
   }
   while (currentHeight > 0) {
     result.push(this.hashByHeight[currentHeight]);
diff --git a/lib/networkmonitor.js b/lib/networkmonitor.js
index fb3435c3..56acfb0a 100644
--- a/lib/networkmonitor.js
+++ b/lib/networkmonitor.js
@@ -65,8 +65,9 @@ NetworkMonitor.prototype.setupPeer = function(peer) {
 };
 
 NetworkMonitor.prototype.requestBlocks = function(start) {
-  $.checkArgument(_.isString(start), 'start must be a block hash string');
-  this.peer.sendMessage(messages.GetBlocks([start]));
+  $.checkArgument(_.isArray(start) ||
+                  _.isString(start), 'start must be a block hash string or array');
+  this.peer.sendMessage(messages.GetBlocks(_.isArray(start) ? start : [start]));
 };
 
 NetworkMonitor.prototype.start = function() {
diff --git a/lib/node.js b/lib/node.js
index 3fc762eb..be57b068 100644
--- a/lib/node.js
+++ b/lib/node.js
@@ -35,7 +35,29 @@ var BitcoreNode = function(bus, networkMonitor, blockService, transactionService
   this.transactionService = transactionService;
   this.blockService = blockService;
 
-  this.bus.register(bitcore.Block, this.blockService.onBlock.bind(this.blockService));
+  this.blockCache = {};
+
+  this.bus.register(bitcore.Block, function(block) {
+
+    var prevHash = bitcore.util.buffer.reverse(block.header.prevHash).toString('hex');
+    self.blockCache[block.hash] = block;
+
+    if (!self.blockchain.hasData(prevHash)) {
+      self.networkMonitor.requestBlocks(self.blockchain.getBlockLocator());
+      return;
+    }
+
+    var blockchainChanges = self.blockchain.proposeNewBlock(block);
+    Promise.each(blockchainChanges.unconfirmed, function(hash) {
+      return self.blockService.unconfirm(self.blockCache[hash]);
+    })
+    .then(Promise.each(blockchainChanges.confirmed, function(hash) {
+      return self.blockService.confirm(self.blockCache[hash]);
+    }))
+    .then(function() {
+      self.networkMonitor.requestBlocks(self.blockchain.getBlockLocator());
+    });
+  });
 
   this.bus.onAny(function(value) {
     self.emit(this.event, value);
@@ -82,8 +104,19 @@ BitcoreNode.create = function(opts) {
 };
 
 BitcoreNode.prototype.start = function() {
-  this.sync();
-  this.networkMonitor.start();
+  var self = this;
+  var genesis = bitcore.Block.fromBuffer(genesisBlocks[bitcore.Networks.defaultNetwork.name]);
+  this.blockService.getBlockchain().then(function(blockchain) {
+    if (!blockchain) {
+      self.blockchain = new BlockChain();
+      self.blockchain.proposeNewBlock(genesis);
+    }
+    self.sync();
+    self.networkMonitor.start();
+  });
+  this.networkMonitor.on('stop', function() {
+    self.blockService.saveBlockchain(self.blockchain);
+  });
 };
 
 BitcoreNode.prototype.stop = function() {
@@ -92,24 +125,15 @@ BitcoreNode.prototype.stop = function() {
 
 
 BitcoreNode.prototype.sync = function() {
-  var genesis = bitcore.Block.fromBuffer(genesisBlocks[bitcore.Networks.defaultNetwork.name]);
   var self = this;
   this.networkMonitor.on('ready', function() {
     self.blockService.getBlockchain().then(function(blockchain) {
-        if (blockchain) {
-          self.blockchain = blockchain;
-        } else {
-          self.blockchain = new BlockChain();
-          self.blockchain.setTip(genesis);
-        }
-        self.networkMonitor.requestBlocks(self.blockchain.tip);
-      })
-      .catch(function(err) {
-        self.networkMonitor.stop();
-        throw err;
-      });
+      self.networkMonitor.requestBlocks(self.blockchain.getBlockLocator());
+    }).catch(function(err) {
+      self.networkMonitor.stop();
+      throw err;
+    });
   });
 };
 
-
 module.exports = BitcoreNode;
diff --git a/lib/services/block.js b/lib/services/block.js
index 3c614035..9a6a0680 100644
--- a/lib/services/block.js
+++ b/lib/services/block.js
@@ -226,9 +226,8 @@ BlockService.prototype.onBlock = function(block) {
  * @param {bitcore.Block} block
  * @return {Promise<Block>} a promise of the same block, for chaining
  */
-BlockService.prototype.save = function(block) {
+BlockService.prototype.unconfirm = function(block) {
   // TODO: unconfirm previous tip, confirm new tip. 
-  return this._confirmBlock(block);
 };
 
 
@@ -238,7 +237,7 @@ BlockService.prototype.save = function(block) {
  * @param {bitcore.Block} block
  * @return {Promise<Block>} a promise of the same block, for chaining
  */
-BlockService.prototype._confirmBlock = function(block) {
+BlockService.prototype.confirm = function(block) {
   $.checkArgument(block instanceof bitcore.Block);
 
   var self = this;