diff --git a/backend/app/services/narrative/narrative_translator.py b/backend/app/services/narrative/narrative_translator.py
new file mode 100644
index 00000000..f6ca2839
--- /dev/null
+++ b/backend/app/services/narrative/narrative_translator.py
@@ -0,0 +1,60 @@
+"""Reads OASIS actions.jsonl and translates rounds into story prose.
+
+The translator is stateless about which round comes next — callers maintain
+the file offset via StoryStore. Each call to `read_actions_for_round` reads
+from the saved offset until a matching `round_end` event is seen (or EOF).
+"""
+import os
+import json
+from typing import List, Tuple
+
+
+def read_actions_for_round(
+    jsonl_path: str, start_offset: int, target_round: int
+) -> Tuple[List[dict], int]:
+    """Read all agent actions for `target_round` starting at `start_offset`.
+
+    Returns:
+        (actions, new_offset): list of action dicts and the file position to
+        resume from on the next read. If the target round hasn't completed yet
+        (no matching `round_end` event), new_offset is advanced to EOF so the
+        next call picks up where we left off.
+    """
+    if not os.path.exists(jsonl_path):
+        return [], start_offset
+
+    actions: List[dict] = []
+    new_offset = start_offset
+
+    with open(jsonl_path, "r", encoding="utf-8") as f:
+        f.seek(start_offset)
+        while True:
+            line = f.readline()
+            if not line:
+                break
+            try:
+                entry = json.loads(line)
+            except json.JSONDecodeError:
+                # Skip malformed lines but keep advancing
+                new_offset = f.tell()
+                continue
+
+            # Round-end event for our target marks the boundary
+            if entry.get("event_type") == "round_end" and entry.get("round") == target_round:
+                new_offset = f.tell()
+                break
+
+            # Skip other event types (simulation_start, simulation_end, etc.)
+            if "event_type" in entry:
+                new_offset = f.tell()
+                continue
+
+            # Skip actions from other rounds
+            if entry.get("round") != target_round:
+                new_offset = f.tell()
+                continue
+
+            actions.append(entry)
+            new_offset = f.tell()
+
+    return actions, new_offset
diff --git a/backend/tests/test_narrative_translator.py b/backend/tests/test_narrative_translator.py
new file mode 100644
index 00000000..750c7843
--- /dev/null
+++ b/backend/tests/test_narrative_translator.py
@@ -0,0 +1,45 @@
+import os
+import json
+import tempfile
+import pytest
+from app.services.narrative.narrative_translator import read_actions_for_round
+
+
+@pytest.fixture
+def actions_file():
+    with tempfile.TemporaryDirectory() as d:
+        path = os.path.join(d, "actions.jsonl")
+        lines = [
+            {"round": 1, "agent_id": 1, "agent_name": "Alice", "action_type": "CREATE_POST",
+             "action_args": {"content": "Hi"}, "success": True, "timestamp": "2026-03-26T12:00:00"},
+            {"round": 1, "agent_id": 2, "agent_name": "Bob", "action_type": "LIKE_POST",
+             "action_args": {"post_id": 1}, "success": True, "timestamp": "2026-03-26T12:00:01"},
+            {"event_type": "round_end", "round": 1, "timestamp": "2026-03-26T12:00:02"},
+            {"round": 2, "agent_id": 1, "agent_name": "Alice", "action_type": "REPOST",
+             "action_args": {}, "success": True, "timestamp": "2026-03-26T12:00:03"},
+        ]
+        with open(path, "w") as f:
+            for line in lines:
+                f.write(json.dumps(line) + "\n")
+        yield path
+
+
+def test_read_actions_for_round_1(actions_file):
+    actions, next_offset = read_actions_for_round(actions_file, start_offset=0, target_round=1)
+    assert len(actions) == 2
+    assert actions[0]["agent_name"] == "Alice"
+    assert actions[1]["agent_name"] == "Bob"
+    assert next_offset > 0
+
+
+def test_read_actions_resumes_from_offset(actions_file):
+    _, offset_after_round_1 = read_actions_for_round(actions_file, start_offset=0, target_round=1)
+    actions, _ = read_actions_for_round(actions_file, start_offset=offset_after_round_1, target_round=2)
+    assert len(actions) == 1
+    assert actions[0]["action_type"] == "REPOST"
+
+
+def test_read_actions_missing_file_returns_empty():
+    actions, offset = read_actions_for_round("/nonexistent/path.jsonl", start_offset=0, target_round=1)
+    assert actions == []
+    assert offset == 0