Make sure you have connected your game to Google Play. It is the only way to save, recover and sync your progress.
- Open Google Play on your device
- Log in to your Google account
- Open Empires & Puzzles and press "Options" on the Main Menu
- Press the "Sign In" button on the bottom of the screen
Your game is now connected!
Please note that Google Play only supports one game per account. Using the same Google Play for more than one account will result in lost progress.