diff --git a/CHANGELOG.md b/CHANGELOG.md
index c128c4e..096ce96 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,7 @@ changed functionality, fixed bugs).
 ## Version 1.1 (in development)
 
 - Add support for Shaman (https://gitlab.com/blender-institute/shaman)
+- Add support for Alembic files referenced in linked-in libraries.
 
 
 ## Version 1.0 (2019-03-01)
diff --git a/blender_asset_tracer/trace/__init__.py b/blender_asset_tracer/trace/__init__.py
index 9623b46..c574f09 100644
--- a/blender_asset_tracer/trace/__init__.py
+++ b/blender_asset_tracer/trace/__init__.py
@@ -51,8 +51,17 @@ def deps(bfilepath: pathlib.Path, progress_cb: typing.Optional[progress.Callback
     if progress_cb:
         bi.progress_cb = progress_cb
 
+    # Remember which block usages we've reported already, without keeping the
+    # blocks themselves in memory.
+    seen_hashes = set()  # type: typing.Set[int]
+
     for block in asset_holding_blocks(bi.iter_blocks(bfile)):
-        yield from blocks2assets.iter_assets(block)
+        for block_usage in blocks2assets.iter_assets(block):
+            usage_hash = hash(block_usage)
+            if usage_hash in seen_hashes:
+                continue
+            seen_hashes.add(usage_hash)
+            yield block_usage
 
 
 def asset_holding_blocks(blocks: typing.Iterable[blendfile.BlendFileBlock]) \
diff --git a/blender_asset_tracer/trace/modifier_walkers.py b/blender_asset_tracer/trace/modifier_walkers.py
index 32e59ea..d227679 100644
--- a/blender_asset_tracer/trace/modifier_walkers.py
+++ b/blender_asset_tracer/trace/modifier_walkers.py
@@ -67,10 +67,17 @@ def modifier_mesh_sequence_cache(ctx: ModifierContext, modifier: blendfile.Blend
                                  block_name: bytes) -> typing.Iterator[result.BlockUsage]:
     """Yield the Alembic file(s) used by this modifier"""
     cache_file = modifier.get_pointer(b'cache_file')
-    path, field = cache_file.get(b'filepath', return_field=True)
+    if cache_file is None:
+        return
 
+    is_sequence = bool(cache_file[b'is_sequence'])
+    cache_block_name = cache_file.id_name
+    assert cache_block_name is not None
+
+    path, field = cache_file.get(b'filepath', return_field=True)
     yield result.BlockUsage(cache_file, path, path_full_field=field,
-                            block_name=b'%s.cache_file' % block_name)
+                            is_sequence=is_sequence,
+                            block_name=cache_block_name)
 
 
 @mod_handler(cdefs.eModifierType_Ocean)
diff --git a/tests/blendfiles/alembic-sequence-source.blend b/tests/blendfiles/alembic-sequence-source.blend
new file mode 100644
index 0000000..29c3e43
Binary files /dev/null and b/tests/blendfiles/alembic-sequence-source.blend differ
diff --git a/tests/blendfiles/alembic-sequence-user.blend b/tests/blendfiles/alembic-sequence-user.blend
new file mode 100644
index 0000000..e890464
Binary files /dev/null and b/tests/blendfiles/alembic-sequence-user.blend differ
diff --git a/tests/blendfiles/clothsim.030.abc b/tests/blendfiles/clothsim.030.abc
new file mode 100644
index 0000000..24e53a0
Binary files /dev/null and b/tests/blendfiles/clothsim.030.abc differ
diff --git a/tests/blendfiles/clothsim.031.abc b/tests/blendfiles/clothsim.031.abc
new file mode 100644
index 0000000..97d8bb1
Binary files /dev/null and b/tests/blendfiles/clothsim.031.abc differ
diff --git a/tests/blendfiles/clothsim.032.abc b/tests/blendfiles/clothsim.032.abc
new file mode 100644
index 0000000..2b56aa7
Binary files /dev/null and b/tests/blendfiles/clothsim.032.abc differ
diff --git a/tests/blendfiles/clothsim.033.abc b/tests/blendfiles/clothsim.033.abc
new file mode 100644
index 0000000..8cc4888
Binary files /dev/null and b/tests/blendfiles/clothsim.033.abc differ
diff --git a/tests/blendfiles/clothsim.034.abc b/tests/blendfiles/clothsim.034.abc
new file mode 100644
index 0000000..2b1fe05
Binary files /dev/null and b/tests/blendfiles/clothsim.034.abc differ
diff --git a/tests/blendfiles/clothsim.035.abc b/tests/blendfiles/clothsim.035.abc
new file mode 100644
index 0000000..e52eae6
Binary files /dev/null and b/tests/blendfiles/clothsim.035.abc differ
diff --git a/tests/test_tracer.py b/tests/test_tracer.py
index 8cca681..f39eb44 100644
--- a/tests/test_tracer.py
+++ b/tests/test_tracer.py
@@ -87,6 +87,9 @@ class DepsTest(AbstractTracerTest):
                 if not exp:
                     # Don't leave empty sets in expects.
                     del expects[dep.block_name]
+            elif exp is None:
+                self.assertIsNone(actual, msg='unexpected dependency of block %s' % dep.block_name)
+                del expects[dep.block_name]
             else:
                 self.assertEqual(exp, actual, msg='for block %s' % dep.block_name)
                 del expects[dep.block_name]
@@ -151,6 +154,25 @@ class DepsTest(AbstractTracerTest):
                                       b'//clothsim.abc', False),
         })
 
+    def test_alembic_sequence(self):
+        self.assert_deps('alembic-sequence-user.blend', {
+            b'CFclothsim_alembic':
+                Expect('CacheFile', 'filepath[1024]', None, None, b'//clothsim.030.abc', True),
+        })
+
+        # Test the filename expansion.
+        expected = [self.blendfiles / ('clothsim.%03d.abc' % num)
+                    for num in range(30, 36)]
+        performed_test = False
+        for dep in trace.deps(self.blendfiles / 'alembic-sequence-user.blend'):
+            if dep.block_name != b'CFclothsim_alembic':
+                continue
+
+            actual = list(dep.files())
+            self.assertEqual(actual, expected)
+            performed_test = True
+        self.assertTrue(performed_test)
+
     def test_block_mc(self):
         self.assert_deps('movieclip.blend', {
             b'MCvideo.mov': Expect('MovieClip', 'name[1024]', None, None,