Simplify the following text for a Grade 11 native English-speaking person.
Original: PokÃ mon Mystery Dungeon : Explorers of Sky is the fifth installment in the PokÃ mon Mystery Dungeon series for the Nintendo DS , and a sister game to PokÃ mon Mystery Dungeon : Explorers of Time and Explorers of Darkness .
Simplified: PokÃ mon Mystery Dungeon : Explorers of Time and PokÃ mon Mystery Dungeon : Explorers of Darkness are a the sequel to the PokÃ mon Mystery Dungeon : Blue Rescue Team and Red Rescue Team games .