diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 5e62f39..f43e7f3 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -106,17 +106,44 @@ jobs:
           restore-keys: |
             ${{ runner.os }}-ccache-node-
 
+      - name: Install OpenSSL (Windows)
+        if: ${{ matrix.platform == 'win32' }}
+        shell: pwsh
+        run: |
+          choco install openssl.light -y --no-progress
+          # Shining Light keeps the x64/MD import libs under lib/VC/x64/MD,
+          # which CMake's FindOpenSSL does not search (and it ignores the
+          # OPENSSL_*_LIBRARY env vars), so stage a standard layout in a
+          # space-free dir and point OPENSSL_ROOT_DIR at it.
+          New-Item -ItemType Directory -Force -Path D:\openssl\lib | Out-Null
+          Copy-Item -Recurse 'C:\Program Files\OpenSSL\include' D:\openssl\
+          Copy-Item 'C:\Program Files\OpenSSL\lib\VC\x64\MD\libcrypto.lib' D:\openssl\lib\
+          Copy-Item 'C:\Program Files\OpenSSL\lib\VC\x64\MD\libssl.lib' D:\openssl\lib\
+          "OPENSSL_ROOT_DIR=D:\openssl" >> $env:GITHUB_ENV
+          # Runtime DLLs (libcrypto/libssl-3-x64.dll) for the test step.
+          'C:\Program Files\OpenSSL\bin' >> $env:GITHUB_PATH
+          Get-ChildItem D:\openssl -Recurse | ForEach-Object { $_.FullName }
+
+      - name: Set up MSVC environment (Windows)
+        if: ${{ matrix.platform == 'win32' }}
+        uses: ilammy/msvc-dev-cmd@v1
+        with:
+          arch: x64
+
       - name: Build Node.js native module (Windows)
         if: ${{ matrix.platform == 'win32' }}
         shell: cmd
         env:
           EXTRA_CMAKE_FLAGS: -DLBUG_NODEJS_ENABLE_TEST_EXPORTS=ON
+          # windows-2025 images ship mingw64 in PATH, which CMake would
+          # otherwise prefer over MSVC (breaking ws2_32 linking and ar).
+          # (cl itself comes from msvc-dev-cmd above via vswhere.)
+          CC: cl
+          CXX: cl
         run: |
           powershell.exe -Command "Add-MpPreference -ExclusionPath '${{ github.workspace }}'"
-          call "C:\Program Files\Microsoft Visual Studio\2022\Enterprise\VC\Auxiliary\Build\vcvars64.bat"
-          ccache -s
-          make GEN=Ninja nodejs
           ccache -s
+          make GEN=Ninja nodejs && ccache -s
 
       - name: Build Node.js native module (non-Windows)
         if: ${{ matrix.platform != 'win32' }}
diff --git a/src_js/connection.js b/src_js/connection.js
index 61f6ef4..8bd6be5 100644
--- a/src_js/connection.js
+++ b/src_js/connection.js
@@ -41,18 +41,23 @@ class Connection {
     if (this._isClosed) {
       throw new Error("Connection is closed.");
     }
-    if (!this._isInitialized) {
-      if (!this._initPromise) {
+    if (this._isInitialized) {
+      return;
+    }
+    if (!this._initPromise) {
+      // Cache the promise synchronously (no await before assignment) so
+      // concurrent init() calls share a single initialization instead of
+      // each starting their own (which crashed the process, see #24).
+      this._initPromise = (async () => {
+        const database = await this._database._getDatabase();
         if (!this._connection) {
-          const database = await this._database._getDatabase();
           this._connection = new LbugNative.NodeConnection(database);
         }
-        this._initPromise = new Promise((resolve, reject) => {
+        await new Promise((resolve, reject) => {
           this._connection.initAsync((err) => {
             if (err) {
               reject(err);
             } else {
-              this._isInitialized = true;
               if (this._numThreads) {
                 this._connection.setMaxNumThreadForExec(this._numThreads);
               }
@@ -63,8 +68,21 @@ class Connection {
             }
           });
         });
+        this._isInitialized = true;
+      })();
+    }
+    const initPromise = this._initPromise;
+    try {
+      await initPromise;
+    } catch (err) {
+      // Allow retry after a failed initialization (clear only if no
+      // newer init has started in the meantime).
+      if (this._initPromise === initPromise) {
+        this._initPromise = null;
       }
-      await this._initPromise;
+      throw err;
+    }
+    if (this._initPromise === initPromise) {
       this._initPromise = null;
     }
   }
diff --git a/test/test_concurrency.js b/test/test_concurrency.js
index 8b70776..3952ecc 100644
--- a/test/test_concurrency.js
+++ b/test/test_concurrency.js
@@ -74,3 +74,55 @@ describe("Concurrent query execution across multiple connections", function () {
     assert.isFalse(results[4][0]["a.isStudent"]);
   });
 });
+
+describe("Concurrent initialization on a fresh connection (issue #24)", function () {
+  it("should handle concurrent queries as the very first use without explicit init", async function () {
+    // Regression test for https://github.com/LadybugDB/ladybug-nodejs/issues/24.
+    // Each iteration uses a fresh in-memory database + connection and fires
+    // two queries concurrently as the first operation. Before the fix, the
+    // lazy-init race in Connection.init() crashed the process (SIGSEGV).
+    // bufferPoolSize 64 MB, maxDBSize 1 GB (the default maxDBSize asks for
+    // an 8 TB mmap, which is too large for some environments).
+    for (let i = 0; i < 50; i++) {
+      const memDb = new lbug.Database(
+        ":memory:",
+        64 * 1024 * 1024,
+        true,
+        false,
+        1024 * 1024 * 1024
+      );
+      const freshConn = new lbug.Connection(memDb);
+      const queryResults = await Promise.all([
+        freshConn.query("RETURN 1 AS x"),
+        freshConn.query("RETURN 2 AS x"),
+      ]);
+      const rows = await Promise.all(
+        queryResults.map((queryResult) => queryResult.getAll())
+      );
+      assert.deepEqual(rows[0], [{ x: 1 }]);
+      assert.deepEqual(rows[1], [{ x: 2 }]);
+      for (const queryResult of queryResults) {
+        queryResult.close();
+      }
+      await freshConn.close();
+      await memDb.close();
+    }
+  });
+
+  it("should handle concurrent init() calls on a fresh connection", async function () {
+    const memDb = new lbug.Database(
+      ":memory:",
+      64 * 1024 * 1024,
+      true,
+      false,
+      1024 * 1024 * 1024
+    );
+    const freshConn = new lbug.Connection(memDb);
+    await Promise.all([freshConn.init(), freshConn.init()]);
+    const queryResult = await freshConn.query("RETURN 1 AS x");
+    assert.deepEqual(await queryResult.getAll(), [{ x: 1 }]);
+    queryResult.close();
+    await freshConn.close();
+    await memDb.close();
+  });
+});