sorry but you can't. you will have to trade it to get it. -RR14
There is not a known Darkrai Action Replay Code for Pokemon HeartGold and SoulSilver yet.
Darkrai cannot be caught or encountered in HeartGold or SoulSilver Versions.
You cannot catch Darkrai in Pokemon Black, you have to transfer it from Diamond, Pearl, Platinum, Heartgold, or Soulsilver.
Darkrai is an event Pokemon, and cannot be found through normal game play. Darkrai thus cannot be found in SoulSilver. Darkrai was an event Pokemon that was available for Diamond and Pearl, but not for SoulSilver.
Pokemon Heartgold and Soulsilver are the remakes of the old Pokemon Gold, Silver, and Crystal series. Pokemon Heartgold and Soulsilver are for the Nintendo DS.
Darkari is unobtainable in heartgold and soulsilver, only to get it is to trade from pearl, diamond, or platinum.
No, there are no underwater routes in Pokemon HeartGold or SoulSilver. The HM Dive is not available in Pokemon HeartGold or SoulSilver.
Extremely difficult actually!! Because Darkrai can only be obtained in Pokemon Ranger: Shadows of Almia by completing a special mission, then transfered to Pkemon Heartgold or Soulsilver... : ^ (
he is not in Pokemon soulsilver or Pokemon heartgold
SOulsilver
That is impossible in Pokemon HeartGold and SoulSilver.
You can only go to Johto and Kanto in Pokemon Heartgold and Soulsilver