You can't every monthmoshi monsters creates a new mission so next month it will be unlocked
You can not unlock the door in the Underground on Moshi Monsters. It is part of Super Moshi Season 1 Mission 2, "Pop Goes the Goo Goo". The door is unlocked as part of the mission, but does not stay unlocked once you complete the mission.
Super Moshi Mission Season 2 Mission 2 has already been released on Moshi Monsters.
Moshi Monsters Super Moshi Season 2 Mission 6 was released in August of 2012.
Season 2 Mission 3 has already been released on Moshi Monsters.
Season 2 Mission 4 on Moshi Monsters has already been released.
Season 2 Mission 5 has already been released on Moshi Monsters.
There is no Mission 13 on Moshi Monsters. They started a new season, so it would be Super Moshi Mission Season 2 Mission 3, which has already been released.
Moshi Monsters Super Moshi Mission 2, Season 2, has already been released.
You have to wait until Moshi Monsters releases each Super Moshi mission. Season 2 Mission 9, which can be found in the Unknown Zone, was released on November 9, 2012. Season 2 Mission 10 should be released sometime in December of 2012.
To get Super Moshi Season 2 Mission 10, you have to wait until Moshi Monsters releases the mission. The Season 2 Super Moshi Missions can be accessed in the Unknown Zone on Moshi Monsters. Season 2 Mission 10 should be released sometime in December of 2012.
There is no "Mission 11" on Moshi Monsters. Instead, they started a new season, so it would be "Season 2 Mission 1" which has already been released.
There are no Epics in Super Moshi Mission 4 Season 1 on Moshi Monsters. Epics were not available in Super Moshi Missions until Season 2 although an Epic has been added to Mission 1 Season 1.