diff --git a/menu_block.services.yml b/menu_block.services.yml
index 983c40a..e0f69d2 100644
--- a/menu_block.services.yml
+++ b/menu_block.services.yml
@@ -4,3 +4,6 @@ services:
     arguments: ['@current_route_match']
     tags:
       - { name: event_subscriber }
+  menu_block.tree_manipulators:
+    class: Drupal\menu_block\MenuLinkTreeManipulators
+    arguments: ['@config.factory']
diff --git a/src/MenuLinkTreeManipulators.php b/src/MenuLinkTreeManipulators.php
new file mode 100644
index 0000000..5d8f0eb
--- /dev/null
+++ b/src/MenuLinkTreeManipulators.php
@@ -0,0 +1,40 @@
+<?php
+
+namespace Drupal\menu_block;
+
+/**
+ * Provides menu link tree manipulators for Menu Block tasks. Manipulators
+ * modify the menu tree to for a specific and limited purpose.
+ */
+class MenuLinkTreeManipulators {
+
+  /**
+   * Config factory.
+   *
+   * @var \Drupal\Core\Config\ConfigFactoryInterface
+   */
+  protected $configFactory;
+
+  /**
+   * Prune a tree so that it starts with an active menu item.
+   *
+   * @param \Drupal\Core\Menu\MenuLinkTreeElement[] $tree
+   *   The menu link tree to manipulate.
+   *
+   * @return \Drupal\Core\Menu\MenuLinkTreeElement[]
+   *   The manipulated menu link tree.
+   */
+  public function pruneActiveTree(array $tree) {
+    $activeTree = [];
+
+    foreach ($tree as $treeElement) {
+      if ($treeElement->inActiveTrail) {
+        $activeTree = [$treeElement];
+        break;
+      }
+    }
+
+    return $activeTree;
+  }
+
+}
diff --git a/src/Plugin/Block/MenuBlock.php b/src/Plugin/Block/MenuBlock.php
index fab522a..a6244dc 100644
--- a/src/Plugin/Block/MenuBlock.php
+++ b/src/Plugin/Block/MenuBlock.php
@@ -161,6 +161,9 @@ class MenuBlock extends SystemMenuBlock {
       array('callable' => 'menu.default_tree_manipulators:checkAccess'),
       array('callable' => 'menu.default_tree_manipulators:generateIndexAndSort'),
     );
+    if ($level > 1) {
+      $manipulators[] = array('callable' => 'menu_block.tree_manipulators:pruneActiveTree');
+    }
     $tree = $this->menuTree->transform($tree, $manipulators);
     $build = $this->menuTree->build($tree);