diff --git a/src/Mapper/Tree/Builder/TreeNode.php b/src/Mapper/Tree/Builder/TreeNode.php
index f32f7df..5d81761 100644
--- a/src/Mapper/Tree/Builder/TreeNode.php
+++ b/src/Mapper/Tree/Builder/TreeNode.php
@@ -145,7 +145,8 @@ final class TreeNode
         }
 
         if ($this->valid && ! $this->shell->type()->accepts($this->value)) {
-            throw new InvalidNodeValue($this->value, $this->shell->type());
+            $this->valid = false;
+            $this->messages[] = new InvalidNodeValue($this->value, $this->shell->type());
         }
     }
 
diff --git a/src/Mapper/Tree/Node.php b/src/Mapper/Tree/Node.php
index 5ba90c2..c73d799 100644
--- a/src/Mapper/Tree/Node.php
+++ b/src/Mapper/Tree/Node.php
@@ -68,6 +68,10 @@ final class Node
             $this->messages[] = $message;
             $this->isValid = $this->isValid && ! $message->isError();
         }
+
+        foreach ($this->children as $child) {
+            $this->isValid = $this->isValid && $child->isValid();
+        }
     }
 
     public function isRoot(): bool
diff --git a/tests/Unit/Mapper/Tree/Builder/TreeNodeTest.php b/tests/Unit/Mapper/Tree/Builder/TreeNodeTest.php
index a5fce42..76f72ba 100644
--- a/tests/Unit/Mapper/Tree/Builder/TreeNodeTest.php
+++ b/tests/Unit/Mapper/Tree/Builder/TreeNodeTest.php
@@ -7,7 +7,6 @@ namespace CuyZ\Valinor\Tests\Unit\Mapper\Tree\Builder;
 use AssertionError;
 use CuyZ\Valinor\Mapper\Tree\Builder\TreeNode;
 use CuyZ\Valinor\Mapper\Tree\Exception\DuplicatedNodeChild;
-use CuyZ\Valinor\Mapper\Tree\Exception\InvalidNodeValue;
 use CuyZ\Valinor\Mapper\Tree\Shell;
 use CuyZ\Valinor\Tests\Fake\Definition\FakeAttributes;
 use CuyZ\Valinor\Tests\Fake\Mapper\Tree\Builder\FakeTreeNode;
@@ -37,15 +36,13 @@ final class TreeNodeTest extends TestCase
         self::assertSame('some value', $node->mappedValue());
     }
 
-    public function test_node_leaf_with_incorrect_value_throws_exception(): void
+    public function test_node_leaf_with_incorrect_value_is_invalid(): void
     {
         $type = new FakeType();
 
-        $this->expectException(InvalidNodeValue::class);
-        $this->expectExceptionCode(1630678334);
-        $this->expectExceptionMessage("Value 'foo' does not match type `{$type->toString()}`.");
+        $node = FakeTreeNode::leaf($type, 'foo');
 
-        FakeTreeNode::leaf($type, 'foo');
+        self::assertFalse($node->isValid());
     }
 
     public function test_node_branch_values_can_be_retrieved(): void
@@ -84,11 +81,9 @@ final class TreeNodeTest extends TestCase
     {
         $type = new FakeType();
 
-        $this->expectException(InvalidNodeValue::class);
-        $this->expectExceptionCode(1630678334);
-        $this->expectExceptionMessage("Value 'foo' does not match type `{$type->toString()}`.");
+        $node = FakeTreeNode::branch([], $type, 'foo');
 
-        FakeTreeNode::branch([], $type, 'foo');
+        self::assertFalse($node->isValid());
     }
 
     public function test_node_error_values_can_be_retrieved(): void
@@ -133,11 +128,9 @@ final class TreeNodeTest extends TestCase
     {
         $type = FakeType::accepting('foo');
 
-        $this->expectException(InvalidNodeValue::class);
-        $this->expectExceptionCode(1630678334);
-        $this->expectExceptionMessage("Value 1337 does not match type `{$type->toString()}`.");
+        $node = FakeTreeNode::leaf($type, 'foo')->withValue(1337);
 
-        FakeTreeNode::leaf($type, 'foo')->withValue(1337);
+        self::assertFalse($node->isValid());
     }
 
     public function test_node_with_invalid_value_for_object_type_returns_invalid_node(): void
@@ -145,11 +138,9 @@ final class TreeNodeTest extends TestCase
         $object = new stdClass();
         $type = FakeObjectType::accepting($object);
 
-        $this->expectException(InvalidNodeValue::class);
-        $this->expectExceptionCode(1630678334);
-        $this->expectExceptionMessage('Invalid value 1337.');
+        $node = FakeTreeNode::leaf($type, $object)->withValue(1337);
 
-        FakeTreeNode::leaf($type, $object)->withValue(1337);
+        self::assertFalse($node->isValid());
     }
 
     public function test_node_with_messages_returns_node_with_messages(): void
diff --git a/tests/Unit/Mapper/Tree/NodeTest.php b/tests/Unit/Mapper/Tree/NodeTest.php
index 9f46fd1..85d72da 100644
--- a/tests/Unit/Mapper/Tree/NodeTest.php
+++ b/tests/Unit/Mapper/Tree/NodeTest.php
@@ -62,6 +62,37 @@ final class NodeTest extends TestCase
         self::assertSame(false, $node->isValid());
     }
 
+    public function test_invalid_child_makes_root_node_not_valid(): void
+    {
+        $message = new FakeErrorMessage();
+
+        $node = new Node(
+            true,
+            '',
+            '*root*',
+            'string',
+            true,
+            'some source value',
+            'some value',
+            [],
+            [
+                new Node(
+                    false,
+                    'nodeName',
+                    'some.node.path',
+                    'string',
+                    true,
+                    'some source value',
+                    'some value',
+                    [$message],
+                    []
+                )
+            ]
+        );
+
+        self::assertSame(false, $node->isValid());
+    }
+
     public function test_get_source_value_not_filled_throws_exception(): void
     {
         $this->expectException(SourceValueWasNotFilled::class);