On Monday, September 28th, 2015 the website, forums, and game log in will be unavailable starting at 4:00am PDT / 6:00 am CDT / 7:00am EDT / 11:00sm UTC/GMT and will end at 11:35am PDT / 1:35pm CDT / 2:35pm EDT / 6:35pm UTC/GMT. Services will be unavailable for an estimated7 hours and 35 minutes.
During that time you'll be unable to log in to the website or the game, but you will not be disconnected from the game if you're already logged in. Game servers will not be affected but players cannot log in during the maintenance.
In the flash sale gambler's box for 5k ncoin, you scroll down and it shows the description... Leona Cube: chance to obtain either an Emperor's Rune (2hour), Emperor's Vitality Tonic, 1 mil SP scroll, 5 mil SP scroll, or 10 mil SP scroll....open the cube once a day for 30 days.