If the event doesn't show for you, the two most likely reasons are:

• You have not downloaded the latest assets for the game. Reboot your device and ensure you're on a strong internet connection. When the loading screen gets to "checking for new assets" you will probably download new assets.
• Your device is not set to automatically sync your date/time. This is necessary for not only events but to also open Timer Coffins. If you are unable to automatically sync for any reason, then you can manually sync your date/time using https://time.is.
• As per the previous point, if you have manually changed your device time, this will affect your main game and any events.

Tip - You may need to reboot your router if you're still not seeing the Event. Unplug your router for 30 seconds, plug it back in, reconnect to WiFi or data and load up the game again.