diff --git a/packages/memory/src/index.ts b/packages/memory/src/index.ts
index a516ebc..863a0a5 100644
--- a/packages/memory/src/index.ts
+++ b/packages/memory/src/index.ts
@@ -1 +1,2 @@
 export * from "./buffer.js";
+export * from "./ledger.js";
diff --git a/packages/memory/src/ledger.ts b/packages/memory/src/ledger.ts
new file mode 100644
index 0000000..69e6d20
--- /dev/null
+++ b/packages/memory/src/ledger.ts
@@ -0,0 +1,228 @@
+import Database from "better-sqlite3";
+
+export interface LedgerEntry {
+  id: string;
+  ownerId: string;
+  timestamp: string;
+  locationId: string | null;
+  involvedEntityIds: string[];
+
+  content: string;
+  quotes: string[];
+  importance: number;
+  embedding: number[];
+}
+
+export class LedgerRepository {
+  constructor(private db: Database.Database) {
+    // Enable foreign keys for cascading deletes
+    this.db.exec("PRAGMA foreign_keys = ON;");
+    this.initializeSchema();
+  }
+
+  private initializeSchema(): void {
+    this.db.exec(`
+      CREATE TABLE IF NOT EXISTS ledger_entries (
+        id TEXT PRIMARY KEY,
+        owner_id TEXT NOT NULL,
+        timestamp TEXT NOT NULL,
+        location_id TEXT,
+        content TEXT NOT NULL,
+        quotes_json TEXT,
+        importance INTEGER NOT NULL,
+        embedding BLOB,
+        FOREIGN KEY (owner_id) REFERENCES objects(id) ON DELETE CASCADE
+      );
+
+      CREATE TABLE IF NOT EXISTS ledger_involved_entities (
+        entry_id TEXT NOT NULL,
+        entity_id TEXT NOT NULL,
+        PRIMARY KEY (entry_id, entity_id),
+        FOREIGN KEY (entry_id) REFERENCES ledger_entries(id) ON DELETE CASCADE
+      );
+    `);
+  }
+
+  save(entry: LedgerEntry): void {
+    const insertEntry = this.db.prepare(`
+      INSERT INTO ledger_entries (id, owner_id, timestamp, location_id, content, quotes_json, importance, embedding)
+      VALUES (?, ?, ?, ?, ?, ?, ?, ?)
+      ON CONFLICT(id) DO UPDATE SET
+        owner_id = excluded.owner_id,
+        timestamp = excluded.timestamp,
+        location_id = excluded.location_id,
+        content = excluded.content,
+        quotes_json = excluded.quotes_json,
+        importance = excluded.importance,
+        embedding = excluded.embedding
+    `);
+
+    const insertEntity = this.db.prepare(`
+      INSERT OR IGNORE INTO ledger_involved_entities (entry_id, entity_id)
+      VALUES (?, ?)
+    `);
+
+    const deleteEntities = this.db.prepare(`
+      DELETE FROM ledger_involved_entities WHERE entry_id = ?
+    `);
+
+    this.db.transaction(() => {
+      insertEntry.run(
+        entry.id,
+        entry.ownerId,
+        entry.timestamp,
+        entry.locationId,
+        entry.content,
+        JSON.stringify(entry.quotes),
+        entry.importance,
+        entry.embedding.length > 0
+          ? Buffer.from(new Float32Array(entry.embedding).buffer)
+          : null
+      );
+
+      deleteEntities.run(entry.id);
+      for (const entityId of entry.involvedEntityIds) {
+        insertEntity.run(entry.id, entityId);
+      }
+    })();
+  }
+
+  load(id: string): LedgerEntry | null {
+    const row = this.db
+      .prepare(
+        `
+      SELECT id, owner_id, timestamp, location_id, content, quotes_json, importance, embedding
+      FROM ledger_entries
+      WHERE id = ?
+    `
+      )
+      .get(id) as any;
+
+    if (!row) return null;
+
+    const entitiesRows = this.db
+      .prepare(
+        `
+      SELECT entity_id FROM ledger_involved_entities WHERE entry_id = ?
+    `
+      )
+      .all(id) as { entity_id: string }[];
+
+    let embedding: number[] = [];
+    if (row.embedding) {
+      const buffer = row.embedding as Buffer;
+      const floatArray = new Float32Array(
+        buffer.buffer,
+        buffer.byteOffset,
+        buffer.byteLength / Float32Array.BYTES_PER_ELEMENT
+      );
+      embedding = Array.from(floatArray);
+    }
+
+    return {
+      id: row.id,
+      ownerId: row.owner_id,
+      timestamp: row.timestamp,
+      locationId: row.location_id,
+      involvedEntityIds: entitiesRows.map((er) => er.entity_id),
+      content: row.content,
+      quotes: JSON.parse(row.quotes_json),
+      importance: row.importance,
+      embedding: embedding,
+    };
+  }
+
+  /**
+   * Retrieves relevant ledger entries using Phase 1: Deterministic Heuristic Filtering
+   * Filters by:
+   * 1. locationId matches current location
+   * 2. involvedEntityIds overlaps with current involved entities
+   * 3. importance >= 8 (high salience)
+   */
+  getRelevant(
+    ownerId: string,
+    currentLocationId: string | null,
+    currentInvolvedEntityIds: string[],
+    limit: number = 20
+  ): LedgerEntry[] {
+    let query = `
+      SELECT DISTINCT le.id, le.owner_id, le.timestamp, le.location_id, le.content, le.quotes_json, le.importance, le.embedding
+      FROM ledger_entries le
+      LEFT JOIN ledger_involved_entities lie ON le.id = lie.entry_id
+      WHERE le.owner_id = ? 
+        AND (
+          le.importance >= 8
+    `;
+
+    const params: any[] = [ownerId];
+
+    if (currentLocationId) {
+      query += ` OR le.location_id = ?`;
+      params.push(currentLocationId);
+    }
+
+    if (currentInvolvedEntityIds.length > 0) {
+      const placeholders = currentInvolvedEntityIds.map(() => "?").join(",");
+      query += ` OR lie.entity_id IN (${placeholders})`;
+      params.push(...currentInvolvedEntityIds);
+    }
+
+    query += `
+        )
+      ORDER BY le.timestamp DESC
+      LIMIT ?
+    `;
+    params.push(limit);
+
+    const rows = this.db.prepare(query).all(...params) as any[];
+
+    if (rows.length === 0) return [];
+
+    const entryIds = rows.map((r) => r.id);
+    const placeholders = entryIds.map(() => "?").join(",");
+    const entitiesRows = this.db
+      .prepare(
+        `
+      SELECT entry_id, entity_id FROM ledger_involved_entities
+      WHERE entry_id IN (${placeholders})
+    `
+      )
+      .all(...entryIds) as { entry_id: string; entity_id: string }[];
+
+    const entitiesMap = new Map<string, string[]>();
+    for (const er of entitiesRows) {
+      if (!entitiesMap.has(er.entry_id)) {
+        entitiesMap.set(er.entry_id, []);
+      }
+      entitiesMap.get(er.entry_id)!.push(er.entity_id);
+    }
+
+    return rows.map((row) => {
+      let embedding: number[] = [];
+      if (row.embedding) {
+        const buffer = row.embedding as Buffer;
+        const floatArray = new Float32Array(
+          buffer.buffer,
+          buffer.byteOffset,
+          buffer.byteLength / Float32Array.BYTES_PER_ELEMENT
+        );
+        embedding = Array.from(floatArray);
+      }
+      return {
+        id: row.id,
+        ownerId: row.owner_id,
+        timestamp: row.timestamp,
+        locationId: row.location_id,
+        involvedEntityIds: entitiesMap.get(row.id) || [],
+        content: row.content,
+        quotes: JSON.parse(row.quotes_json),
+        importance: row.importance,
+        embedding: embedding,
+      };
+    });
+  }
+
+  delete(id: string): void {
+    this.db.prepare(`DELETE FROM ledger_entries WHERE id = ?`).run(id);
+  }
+}
diff --git a/packages/memory/tests/ledger.test.ts b/packages/memory/tests/ledger.test.ts
new file mode 100644
index 0000000..8f28b31
--- /dev/null
+++ b/packages/memory/tests/ledger.test.ts
@@ -0,0 +1,124 @@
+import { describe, it, expect, beforeEach, afterEach } from "vitest";
+import Database from "better-sqlite3";
+import { LedgerRepository, LedgerEntry } from "../src/ledger";
+
+describe("LedgerRepository", () => {
+  let db: Database.Database;
+  let repo: LedgerRepository;
+
+  beforeEach(() => {
+    db = new Database(":memory:");
+    
+    // We need to create a dummy objects table to satisfy foreign keys
+    db.exec(`
+      CREATE TABLE objects (
+        id TEXT PRIMARY KEY
+      );
+    `);
+
+    db.exec(`
+      INSERT INTO objects (id) VALUES ('alice'), ('bob'), ('charlie');
+    `);
+
+    repo = new LedgerRepository(db);
+  });
+
+  afterEach(() => {
+    db.close();
+  });
+
+  it("should save and load a ledger entry", () => {
+    const entry: LedgerEntry = {
+      id: "mem1",
+      ownerId: "alice",
+      timestamp: new Date().toISOString(),
+      locationId: "loc1",
+      involvedEntityIds: ["bob", "charlie"],
+      content: "Alice met Bob and Charlie at the market.",
+      quotes: ["Hi guys!"],
+      importance: 5,
+      embedding: [0.1, 0.2, 0.3],
+    };
+
+    repo.save(entry);
+
+    const loaded = repo.load("mem1");
+    expect(loaded).toBeDefined();
+    expect(loaded?.id).toBe("mem1");
+    expect(loaded?.ownerId).toBe("alice");
+    expect(loaded?.locationId).toBe("loc1");
+    expect(loaded?.involvedEntityIds.sort()).toEqual(["bob", "charlie"].sort());
+    expect(loaded?.content).toBe(entry.content);
+    expect(loaded?.quotes).toEqual(entry.quotes);
+    expect(loaded?.importance).toBe(5);
+    
+    // Check float precision
+    expect(loaded?.embedding[0]).toBeCloseTo(0.1);
+    expect(loaded?.embedding[1]).toBeCloseTo(0.2);
+    expect(loaded?.embedding[2]).toBeCloseTo(0.3);
+  });
+
+  it("should return null for non-existent entry", () => {
+    const loaded = repo.load("missing");
+    expect(loaded).toBeNull();
+  });
+
+  it("should retrieve relevant memories based on Phase 1 heuristics", () => {
+    repo.save({
+      id: "mem_high_salience",
+      ownerId: "alice",
+      timestamp: "2024-01-01T10:00:00.000Z",
+      locationId: "loc2",
+      involvedEntityIds: [],
+      content: "Alice found a magical sword.",
+      quotes: [],
+      importance: 9, // high salience
+      embedding: [],
+    });
+
+    repo.save({
+      id: "mem_location",
+      ownerId: "alice",
+      timestamp: "2024-01-02T10:00:00.000Z",
+      locationId: "loc1", // matches query
+      involvedEntityIds: [],
+      content: "Alice sat on a bench.",
+      quotes: [],
+      importance: 2,
+      embedding: [],
+    });
+
+    repo.save({
+      id: "mem_social",
+      ownerId: "alice",
+      timestamp: "2024-01-03T10:00:00.000Z",
+      locationId: "loc2",
+      involvedEntityIds: ["bob"], // matches query
+      content: "Alice waved at Bob.",
+      quotes: [],
+      importance: 3,
+      embedding: [],
+    });
+
+    repo.save({
+      id: "mem_irrelevant",
+      ownerId: "alice",
+      timestamp: "2024-01-04T10:00:00.000Z",
+      locationId: "loc3",
+      involvedEntityIds: ["charlie"],
+      content: "Alice sneezed.",
+      quotes: [],
+      importance: 2,
+      embedding: [],
+    });
+
+    const relevant = repo.getRelevant("alice", "loc1", ["bob"]);
+    
+    expect(relevant).toHaveLength(3);
+    const ids = relevant.map((r) => r.id);
+    expect(ids).toContain("mem_high_salience"); // due to importance >= 8
+    expect(ids).toContain("mem_location"); // due to locationId
+    expect(ids).toContain("mem_social"); // due to involvedEntityIds
+    expect(ids).not.toContain("mem_irrelevant");
+  });
+});