diff --git a/src/Composer/Plugin/ExtraDownloadsPlugin.php b/src/Composer/Plugin/ExtraDownloadsPlugin.php
new file mode 100644
index 0000000..7971cd0
--- /dev/null
+++ b/src/Composer/Plugin/ExtraDownloadsPlugin.php
@@ -0,0 +1,92 @@
+<?php
+
+namespace LastCall\DownloadsPlugin\Composer\Plugin;
+
+use Composer\Composer;
+use Composer\DependencyResolver\Operation\InstallOperation;
+use Composer\DependencyResolver\Operation\UpdateOperation;
+use Composer\EventDispatcher\EventSubscriberInterface;
+use Composer\Installer\PackageEvent;
+use Composer\Installer\PackageEvents;
+use Composer\IO\IOInterface;
+use Composer\Plugin\PluginInterface;
+use Composer\Script\Event;
+use Composer\Script\ScriptEvents;
+use LastCall\DownloadsPlugin\Composer\Installer\ArchiveInstaller;
+use LastCall\DownloadsPlugin\Composer\Installer\FileInstaller;
+use LastCall\DownloadsPlugin\Exception\OutOfRangeException;
+use LastCall\DownloadsPlugin\Handler\PackageHandler;
+use LastCall\DownloadsPlugin\Handler\PackageHandlerInterface;
+
+class ExtraDownloadsPlugin implements PluginInterface, EventSubscriberInterface
+{
+    private const EVENT_PRIORITY = 10;
+
+    public function __construct(private ?PackageHandlerInterface $handler = null)
+    {
+    }
+
+    public static function getSubscribedEvents(): array
+    {
+        return [
+            PackageEvents::POST_PACKAGE_INSTALL => ['handlePackageEvent', self::EVENT_PRIORITY],
+            PackageEvents::POST_PACKAGE_UPDATE => ['handlePackageEvent', self::EVENT_PRIORITY],
+            ScriptEvents::POST_INSTALL_CMD => ['handleScriptEvent', self::EVENT_PRIORITY],
+            ScriptEvents::POST_UPDATE_CMD => ['handleScriptEvent', self::EVENT_PRIORITY],
+        ];
+    }
+
+    public function handleScriptEvent(Event $event): void
+    {
+        $rootPackage = $event->getComposer()->getPackage();
+        $this->getHandler($event->getComposer(), $event->getIO())->handle($rootPackage);
+
+        // Ensure that any other packages are properly reconciled.
+        $localRepo = $event->getComposer()->getRepositoryManager()->getLocalRepository();
+        foreach ($localRepo->getCanonicalPackages() as $package) {
+            $this->getHandler($event->getComposer(), $event->getIO())->handle($package);
+        }
+    }
+
+    public function handlePackageEvent(PackageEvent $event): void
+    {
+        $package = match (\get_class($event->getOperation())) {
+            InstallOperation::class => $event->getOperation()->getPackage(),
+            UpdateOperation::class => $event->getOperation()->getTargetPackage(),
+            default => throw new OutOfRangeException(sprintf('Operation %s not supported', $event->getOperation()->getOperationType()))
+        };
+        $this->getHandler($event->getComposer(), $event->getIO())->handle($package);
+    }
+
+    public function activate(Composer $composer, IOInterface $io): void
+    {
+        $this->addInstallers($composer, $io);
+    }
+
+    public function deactivate(Composer $composer, IOInterface $io): void
+    {
+    }
+
+    public function uninstall(Composer $composer, IOInterface $io): void
+    {
+    }
+
+    private function addInstallers(Composer $composer, IOInterface $io): void
+    {
+        $installers = [
+            new ArchiveInstaller($io, $composer),
+            new FileInstaller($io, $composer),
+        ];
+        $installationManager = $composer->getInstallationManager();
+        foreach ($installers as $installer) {
+            $installationManager->addInstaller($installer);
+        }
+    }
+
+    private function getHandler(Composer $composer, IOInterface $io): PackageHandlerInterface
+    {
+        $this->handler ??= new PackageHandler($composer, $io);
+
+        return $this->handler;
+    }
+}
diff --git a/src/Exception/OutOfRangeException.php b/src/Exception/OutOfRangeException.php
index 4410ae8..08ba380 100644
--- a/src/Exception/OutOfRangeException.php
+++ b/src/Exception/OutOfRangeException.php
@@ -2,6 +2,6 @@
 
 namespace LastCall\DownloadsPlugin\Exception;
 
-class OutOfRangeException extends \OutOfRangeException
+class OutOfRangeException extends BaseException
 {
 }
diff --git a/src/Exception/UnexpectedValueException.php b/src/Exception/UnexpectedValueException.php
index ddce5d3..2d54874 100644
--- a/src/Exception/UnexpectedValueException.php
+++ b/src/Exception/UnexpectedValueException.php
@@ -2,6 +2,6 @@
 
 namespace LastCall\DownloadsPlugin\Exception;
 
-class UnexpectedValueException extends \UnexpectedValueException
+class UnexpectedValueException extends BaseException
 {
 }
diff --git a/tests/Unit/Composer/Plugin/ExtraDownloadsPluginTest.php b/tests/Unit/Composer/Plugin/ExtraDownloadsPluginTest.php
new file mode 100644
index 0000000..199c004
--- /dev/null
+++ b/tests/Unit/Composer/Plugin/ExtraDownloadsPluginTest.php
@@ -0,0 +1,163 @@
+<?php
+
+namespace LastCall\DownloadsPlugin\Tests\Unit\Composer\Plugin;
+
+use Composer\Composer;
+use Composer\DependencyResolver\Operation\InstallOperation;
+use Composer\DependencyResolver\Operation\UninstallOperation;
+use Composer\DependencyResolver\Operation\UpdateOperation;
+use Composer\Installer\InstallationManager;
+use Composer\Installer\PackageEvent;
+use Composer\Installer\PackageEvents;
+use Composer\IO\IOInterface;
+use Composer\Package\PackageInterface;
+use Composer\Package\RootPackageInterface;
+use Composer\Repository\InstalledRepositoryInterface;
+use Composer\Repository\RepositoryInterface;
+use Composer\Repository\RepositoryManager;
+use Composer\Script\Event;
+use Composer\Script\ScriptEvents;
+use LastCall\DownloadsPlugin\Composer\Installer\ArchiveInstaller;
+use LastCall\DownloadsPlugin\Composer\Installer\FileInstaller;
+use LastCall\DownloadsPlugin\Composer\Plugin\ExtraDownloadsPlugin;
+use LastCall\DownloadsPlugin\Exception\OutOfRangeException;
+use LastCall\DownloadsPlugin\Handler\PackageHandlerInterface;
+use PHPUnit\Framework\MockObject\MockObject;
+use PHPUnit\Framework\TestCase;
+
+class ExtraDownloadsPluginTest extends TestCase
+{
+    private PackageHandlerInterface|MockObject $handler;
+    private ExtraDownloadsPlugin $plugin;
+    private Composer|MockObject $composer;
+    private IOInterface|MockObject $io;
+    private InstallationManager|MockObject $installationManager;
+
+    protected function setUp(): void
+    {
+        $this->handler = $this->createMock(PackageHandlerInterface::class);
+        $this->plugin = new ExtraDownloadsPlugin($this->handler);
+        $this->composer = $this->createMock(Composer::class);
+        $this->io = $this->createMock(IOInterface::class);
+        $this->installationManager = $this->createMock(InstallationManager::class);
+    }
+
+    public function testGetSubscribedEvents(): void
+    {
+        $this->assertSame([
+            PackageEvents::POST_PACKAGE_INSTALL => ['handlePackageEvent', 10],
+            PackageEvents::POST_PACKAGE_UPDATE => ['handlePackageEvent', 10],
+            ScriptEvents::POST_INSTALL_CMD => ['handleScriptEvent', 10],
+            ScriptEvents::POST_UPDATE_CMD => ['handleScriptEvent', 10],
+        ], ExtraDownloadsPlugin::getSubscribedEvents());
+    }
+
+    public function testActivate(): void
+    {
+        $this->composer
+            ->expects($this->once())
+            ->method('getInstallationManager')
+            ->willReturn($this->installationManager);
+        $this->installationManager
+            ->expects($this->exactly(2))
+            ->method('addInstaller')
+            ->withConsecutive(
+                [$this->isInstanceOf(ArchiveInstaller::class)],
+                [$this->isInstanceOf(FileInstaller::class)],
+            );
+        $this->plugin->activate($this->composer, $this->io);
+    }
+
+    public function testDeactivate(): void
+    {
+        $this->expectNotToPerformAssertions();
+        $this->plugin->deactivate($this->composer, $this->io);
+    }
+
+    public function testUninstall(): void
+    {
+        $this->expectNotToPerformAssertions();
+        $this->plugin->uninstall($this->composer, $this->io);
+    }
+
+    public function testHandleScriptEvent(): void
+    {
+        $rootPackage = $this->createMock(RootPackageInterface::class);
+        $this->composer->expects($this->once())->method('getPackage')->willReturn($rootPackage);
+        $repositoryManager = $this->createMock(RepositoryManager::class);
+        $this->composer->expects($this->once())->method('getRepositoryManager')->willReturn($repositoryManager);
+        $localRepository = $this->createMock(InstalledRepositoryInterface::class);
+        $repositoryManager->expects($this->once())->method('getLocalRepository')->willReturn($localRepository);
+        $packages = [
+            $this->createMock(PackageInterface::class),
+            $this->createMock(PackageInterface::class),
+            $this->createMock(PackageInterface::class),
+        ];
+        $localRepository->expects($this->once())->method('getCanonicalPackages')->willReturn($packages);
+        $this->handler
+            ->expects($this->exactly(\count($packages) + 1))
+            ->method('handle')
+            ->withConsecutive(
+                [$rootPackage],
+                ...array_map(fn (PackageInterface $package) => [$package], $packages),
+            );
+        $event = new Event('name', $this->composer, $this->io);
+        $this->plugin->handleScriptEvent($event);
+    }
+
+    public function testHandleInstallPackageEvent(): void
+    {
+        $package = $this->createMock(PackageInterface::class);
+        $this->handler
+            ->expects($this->once())
+            ->method('handle')
+            ->with($package);
+        $event = new PackageEvent(
+            'install',
+            $this->composer,
+            $this->io,
+            false,
+            $this->createMock(RepositoryInterface::class),
+            [],
+            new InstallOperation($package)
+        );
+        $this->plugin->handlePackageEvent($event);
+    }
+
+    public function testHandleUpdatePackageEvent(): void
+    {
+        $initial = $this->createMock(PackageInterface::class);
+        $target = $this->createMock(PackageInterface::class);
+        $this->handler
+            ->expects($this->once())
+            ->method('handle')
+            ->with($target);
+        $event = new PackageEvent(
+            'update',
+            $this->composer,
+            $this->io,
+            false,
+            $this->createMock(RepositoryInterface::class),
+            [],
+            new UpdateOperation($initial, $target)
+        );
+        $this->plugin->handlePackageEvent($event);
+    }
+
+    public function testHandleUninstallPackageEvent(): void
+    {
+        $this->expectException(OutOfRangeException::class);
+        $this->expectExceptionMessage('Operation uninstall not supported');
+        $package = $this->createMock(PackageInterface::class);
+        $event = new PackageEvent(
+            'uninstall',
+            $this->composer,
+            $this->io,
+            false,
+            $this->createMock(RepositoryInterface::class),
+            [],
+            new UninstallOperation($package)
+        );
+        $this->plugin->handlePackageEvent($event);
+    }
+}