Pokémon Gois giving players new incentives to keep coming back to the already addictive app: a storyline,Winter Wonderlust (2015) daily quests, and an elusive legendary Pokémon.

The latest Pokémon Goupdate adds Field Research and Special Research features which give players more activities to do. The latter adds a bit of a story element to the game for the first time since its launch. Completing research tasks nets players rewards and can lead to an encounter with a legendary Pokémon, including the new Mew.

Field Research quests are unlocked by going to PokéStops and players can complete multiple Field Research quests per day. The quests are described vaguely by Niantic as "a wide range of Pokémon-related activities," which is kind of a no-brainer, but likely will be challenges like catching specific Pokémon or completing an event.

More challenging quests will give players better rewards, and as players complete more quests they'll be able to cash-in for even better rewards with a new stamp system.

"Trainers can also earn one stamp per day by completing at least one Field Research task," Niantic said in a blog post. "When Trainers collect seven stamps, they can achieve a Research Breakthrough to receive even greater rewards — perhaps even an encounter with a legendary Pokémon."

Meanwhile, the Special Research tasks will be given to players from Professor Willow and will have unique storylines that unravel over time and lead to discovering the mystery behind Mew.

Mew will start appearing around the world soon, and players will begin receiving Special Research quests later this week.