Time Gears are a major feature in the games Pokémon Mystery Dungeon: Explorers of Time and Pokémon Mystery Dungeon: Explorers of Darkness. The function of these Time Gears is to control time in the Pokémon world. Their appearance is that of a cog and they give off an aura of blue and green.
As mentioned before, the Time Gears are a major part of the storyline for the new Pokémon Mystery Dungeon games. Their sheer existence determines how time will run, or not run if things go bad.
When you begin the game, you will slowly learn about these Time Gears and how they are linked to the functions of time itself in the world. These Time Gears are spread out across the globe, each in a special area making sure time functions correctly. Some Pokémon are specially selected to protect these Time Gears with their lives and to do whatever is necessary for the sake of everyone.
Little do they know that the Time Gears are linked to Temporal Tower, home of Dialga. This building resides in the Hidden Land, out of the way and knowledge of any Pokémon. You get there by taking transport on the back of a Lapras who you will run into a couple of times. At the top of the tower is a wall with imprints to allow the Time Gears to be slotted into them, which is where they should remain for all time to keep time flowing correctly.
The Time Gears are linked to numerous characters who play their role within the storyline. Those of mention include the three Fairy Pokémon of Sinnoh (Uxie, Mesprit and Azelf), Primal Dialga, Dusknoir and of the most worthy mention being Grovyle.
Uxie, Mesprit and Azelf
These three Pokémon protect three of the Time Gears respectively. They, however, prove to be no match for Grovyle in battle and are systematically swept aside. Azelf proves to be the best of the three as being more prepared it had set a trap, upon reaching the Time Gears Azelf triggered it and crystals shot up from the ground all around the glowing cog to protect it from being stolen.
Primal Dialga, previously known as just Dialga, can be considered the main culprit behind the stopping of time. Corrupted, in the future Primal Dialga reigns as the supreme ruler of all the world. Dusknoir may be considered its right-hand man along with all the Sableye acting as minions. It's Primal Dialga's wish to have Grovyle, your partner along with yourself utterly destroyed to ensure that ultimate power is not lost.
After the Time Gears have been returned to Temporal Tower back in the past, you must battle Primal Dialga in order to get it to see reason. Upon winning the battle, it's body shall be purified and before you shall stand the elegant Dialga, Ruler of time. You will be thanked, along with Dialga returning the favour by bringing you hurling back through time to your partner after disappearing from the change in history.
Dusknoir, also known as The Great Dusknoir, plays a big role throughout the vast majority of the storyline. He first appears in Treasure Town to great happiness from the locals. Intentions unclear, Dusknoir tends to hang around Wigglytuff's Guild and gives out advice and pieces of wisdom to the locals.
Dusknoir comes to the help of your partner and yourself a couple of times. This is in response to an attack by Grovyle, who talk to one another as if knowing each other. Dusknoir after this point helps the Guild in their attempt to capture him and bring him to justice and when you go to retrieve an item for Marill and Azurill.
Later on it is discovered that he and Grovyle are both from the future, a dark future. A future where Grovyle is a wanted criminal and has come to the past to ensure the destruction of the world. Dusknoir says that it was a duty given to him to bring him back.
Upon the capturing of the evil Pokémon, Dusknoir creates a rift in time in Treasure Town to return to the future. His true intentions reveal themselves, as before he leaves he shall reach out to grab your partner and yourself and suck you into the future with him.
It's in the future you learn that Grovyle is the good guy and that Dusknoir is actually working for the main evil character. You then progress to escaping back into the past before meeting Dusknoir again at the Rainbow Stoneship when he attempts to stop you. You must then defeat him and his Sableye Squad before further progression in the game can be made.
Grovyle is introduced as a shady character of immense power, stopping at nothing until all the Time Gears are stolen. At first you only see him in cut-scenes, flashing quickly on the screen in the dark by the thunder and lightning. Further on you begin to see him in his true form as he attacks the three Fairies to obtain the Time Gears. Dusknoir thwarts his plans and arrests him, progressing to open up a portal and take him back to the future. You get taken with with them and end up tied to a sacrifice pole along with your partner and Grovyle. You manage to escape and run into him a couple of times on your journey back to your own time. You realise Grovyle is the good guy and end up joining forces with him to go to Temporal Tower and defeat Dialga. You lost him, however, as Dusknoir catches you again and he drags him back into the portal so that you and your partner may continue. After defeating Dialga, Grovyle ceases to exist after his last heroic action.