diff --git a/polbin/src/file.rs b/polbin/src/file.rs
new file mode 100644
index 00000000..f228b004
--- /dev/null
+++ b/polbin/src/file.rs
@@ -0,0 +1,49 @@
+use crate::flatgfa;
+use bstr::BStr;
+use zerocopy::{FromBytes, FromZeroes};
+
+const MAGIC_NUMBER: usize = 0x1337_4915;
+
+#[derive(FromBytes, FromZeroes)]
+struct TOC {
+    magic: usize,
+    header_len: usize,
+    segs_count: usize,
+    paths_count: usize,
+    links_count: usize,
+    steps_count: usize,
+    seq_data_len: usize,
+    overlaps_count: usize,
+    alignment_len: usize,
+    name_data_len: usize,
+    optional_data_len: usize,
+    line_order_len: usize,
+}
+
+pub fn load(data: &[u8]) -> flatgfa::FlatGFA {
+    // Table of contents.
+    let toc = TOC::ref_from_prefix(data).unwrap();
+    let rest = &data[std::mem::size_of::<TOC>()..];
+    assert_eq!(toc.magic, MAGIC_NUMBER);
+
+    // Header (version).
+    let header = BStr::new(&rest[0..toc.header_len]);
+    let rest = &rest[toc.header_len..];
+
+    // Segments.
+    let (segs, rest) = flatgfa::Segment::slice_from_prefix(rest, toc.segs_count).unwrap();
+
+    flatgfa::FlatGFA {
+        header,
+        segs,
+        paths: todo!(),
+        links: todo!(),
+        steps: todo!(),
+        seq_data: todo!(),
+        overlaps: todo!(),
+        alignment: todo!(),
+        name_data: todo!(),
+        optional_data: todo!(),
+        line_order: todo!(),
+    }
+}