simple use a master ball i thing only master ball because giritina is a legendery and normal pokeballs don't work
EDIT: Turn back cave is in the distortion world located at spear pillar.
In DP, it would be the Turnback Cave in the Spring Path after you beat the elite 4. In Platinum, it would be in the Distortion World (It like a giant puzzle).
Well to get Garitina use the master ball to catch Garitina or some dusks balls or timer balls or some quick balls.
You can't catch Garitina on Pokemon White.
If you kill Garitina on diamond, you will kill am and never have him. i would recommend saving before you catch Garitina.
You have to battle garitina and cynthia will lead you to sendoff springs use rock climb and you will get to spring path it will lead you to route 214
to catch a gariina you have to use a master ball from cyrus
You get it in the distortion world
catch or defete garitina
u cant
You go and get a action replay and get the rest or get darkri with the event
a master ball