Cinawood city, which is in the next town after the one with the lighthouse.
well....you go to the light house and she askes you to get medacine for the lighthouse Pokemon and the medacine is in cainwood city its acros the ocean at the beach in olavine city to get past the man you have to get the hm surf he will say were it is.
In olivine city.
there will be a secret door at olivines lighthouse and it will take you to jasmine then go back to the gym then jasmine will battle you
To get the Olivine City Gym leader to battle you, you have to go to the top of the lighthouse and help her heal a Pokemon by getting medicine from a man across the sea in Cianwood. The leader there, Chuck, is actually the fifth, and Jasmine is the sixth.
You have to beat Cianwood gym, get the medicine from the Cianwood medicine shop, and take it to the top of the lighthouse. Then, the gym leader of Olivine will fight you. Good luck!
When you have beaten team rocket, you can find her in the lighthouse
in order to do that you have to help the lady in the lighthouse
Secret Potion
The fourth gym leader in Pokemon Soul Silver is in Ecruteak City.
you go to the city before the safarie zone.
get a Pokemon with a ressisstance
Get an S.S. Ticket from Prof. Elm(i believe its elm) then take to ship to kanto and the gym leader is in the lighthouse with a sick pokemon, you then talk to her and get the medicine and bring it back to her. Once this is done she will return to her gym