diff --git a/python/pmtiles/reader.py b/python/pmtiles/reader.py
index f5aa366..09a7ea0 100644
--- a/python/pmtiles/reader.py
+++ b/python/pmtiles/reader.py
@@ -72,6 +72,8 @@ class Reader:
         else:
             if len(self.header().leaves) > 0:
                 level_diff = z - self._leaf_level()
+                if level_diff < 0:
+                    return None
                 leaf = (
                     self._leaf_level(),
                     x // (1 << level_diff),
diff --git a/python/test/test_reader.py b/python/test/test_reader.py
index 5e57a9d..42b8d1b 100644
--- a/python/test/test_reader.py
+++ b/python/test/test_reader.py
@@ -7,11 +7,10 @@ from pmtiles.reader import Reader, MemorySource
 class TestReader(unittest.TestCase):
     def test_roundtrip(self):
         buf = BytesIO()
-        writer = Writer(buf, 7)
+        writer = Writer(buf, 5)
         writer.write_tile(1, 0, 0, b"0")
         writer.write_tile(1, 0, 1, b"1")
         writer.write_tile(1, 1, 0, b"2")
-        writer.write_tile(1, 1, 1, b"3")
         writer.write_tile(2, 0, 0, b"4")
         writer.write_tile(3, 0, 0, b"5")
         writer.write_tile(2, 0, 1, b"6")
@@ -24,8 +23,8 @@ class TestReader(unittest.TestCase):
         self.assertEqual(reader.get(1, 0, 0), b"0")
         self.assertEqual(reader.get(1, 0, 1), b"1")
         self.assertEqual(reader.get(1, 1, 0), b"2")
-        self.assertEqual(reader.get(1, 1, 1), b"3")
         self.assertEqual(reader.get(2, 0, 0), b"4")
         self.assertEqual(reader.get(3, 0, 0), b"5")
         self.assertEqual(reader.get(2, 0, 1), b"6")
         self.assertEqual(reader.get(3, 0, 2), b"7")
+        self.assertEqual(reader.get(1, 1, 1), None)