No, since you have to beat Giratina to go to Sunyshore City. There is a WaterFall in the Distortion World though, but you only need waterfall to climb, no fall.
Chat with our AI personalities
its been confirmed you can catch it in Pokemon platinum pearl and diamond
You need to catch Giratina or beat Giratina after that go to Lake Verity. You need HM Surf...
In turn back cave
Yes, but if you want to catch giratina later you can go to turn back cave.
catch or kill giratina the you'll go to sendoff spring haunter is somewhere there. NOTE if you dont believe me kill or catch giratina go in the portal where giratina was then look on the map!