Speedville is a run down town that was built by Sir Charles as a haven for all racers. Racers from all around the world used to go to Speedville for races on the "Legendary Tracks". However somewhere down the road Sims became less and less interested in racing and things got slow. Now the town needs a Sim to reinvigorate the love of racing. That's where you come in.
You start by arriving as a racer who came to Speedville and after offering to help Sir Charles after his plea for a racer to revive the dying town. You then drive with Sir Charles to meet Ol' Gabby, an old friend of his, who then takes you to his Workshop, your House, and then the Town race tracks to participate in your first race on MySims™ Raceway. Afterwards you winning the race has caused the town to gain a Star Level allowing a new track and a new area of town to be opened up, from there winning races will unlock Blueprints for Vehicle upgrades and raise your Star Level. You are also able to take Favors from the townspeople to earn Essence Coins, as well as Blueprints for new outfits and Vehicle parts.
Quick Race allows you to use your Sim to race on all the tracks you have unlocked thus far. You are allowed to change the difficulty of the NPC racers using a scale of stars ranging from 1 (Easiest) to 5 (Hardest)
Multiplayer allows you to play the game with one or more friends if they have the game by selecting Multi-Card Play, or if they don't by selecting Single-Card Play and using DS Download Play to play the game. You were also able to play online with Friends or Strangers. However this is no longer possible due to the Nintendo Wifi Connection officially shutting down on May 20, 2014.
In Create-A-Sim you are allowed to create a Sim of either gender, Male or Female, and tweak them to your liking. They have various attributes that can be changed such as; Skin Color, Eyes, Voice, Hair/Hat, Clothes, and their colors using a color "wheel" comprising of 79 total colors. You can change aspects of your sim later on at your house.
At Gabby's Workshop you can spend Red, Green, and Blue Essence Coins to create upgrades from blueprints for your vehicle to increase performance, and apply them to your vehicle. Pink, Yellow, and Purple Essence Coins to create new parts from blueprints on your vehicle and Create-A-Sim items, you can also apply the parts to your vehicle and choose the paint color from the same color "wheel".
The game features a large array of Power-Ups (similar to the "items" of Mario Kart) which can be used during races to hinder Rival Racers.
Pumpkin - When thrown creates a puddle that causes your vehicle to spin out. Also comes in a pack of three.
Acorn - When thrown and hits the ground creates a large tree that disappears after either you or a Rival Racers hits it. Also comes in a pack of three.
UFO - When used summons a UFO to carry you across the track in order to catch up with your Rival Racers. Only appears in lower positions.
Soccer Ball - When thrown can either directly target a Rival Racers in front of you or ricochets off of walls. Also comes in a pack of three.
Shield - When used coats your vehicle in a protective layer of metallic armor that negates the effects of all Power-Ups
MySims Racing DS has a total of 22 characters, of which only 8 are actual racers these include:
Fire chief Ginny