diff --git a/include/yaml-cpp/node/detail/impl.h b/include/yaml-cpp/node/detail/impl.h
index e22bc70..5931826 100644
--- a/include/yaml-cpp/node/detail/impl.h
+++ b/include/yaml-cpp/node/detail/impl.h
@@ -32,7 +32,7 @@ struct get_idx<Key,
 
   static node* get(std::vector<node*>& sequence, const Key& key,
                    shared_memory_holder pMemory) {
-    if (key > sequence.size())
+   if (key > sequence.size() || (key > 0 && !sequence[key-1]->is_defined()))
       return 0;
     if (key == sequence.size())
       sequence.push_back(&pMemory->create_node());
diff --git a/test/node/node_test.cpp b/test/node/node_test.cpp
index b5ba155..485ad09 100644
--- a/test/node/node_test.cpp
+++ b/test/node/node_test.cpp
@@ -88,11 +88,22 @@ TEST(NodeTest, MapWithUndefinedValues) {
   EXPECT_EQ(2, node.size());
 }
 
+TEST(NodeTest, SeqIntoMap) {
+  Node node;
+  node[0] = "test";
+  node[1];
+  node[2] = "value";
+  EXPECT_TRUE(node.IsMap());
+  EXPECT_EQ("test", node[0].as<std::string>());
+  EXPECT_EQ("value", node[2].as<std::string>());
+  EXPECT_EQ(2, node.size());
+}
+
 TEST(NodeTest, RemoveUnassignedNode) {
   Node node(NodeType::Map);
   node["key"];
   node.remove("key");
-  EXPECT_EQ(node.size(), 0);
+  EXPECT_EQ(0, node.size());
 }
 
 TEST(NodeTest, MapForceInsert) {