。
I wonder if something nice will happen.
Literal
Something good thing not-exist [I-wonder-かな].
Rhetorical musing. 何かいいこと ('something good') + ない (negative of ある, 'doesn't exist') + かな ('I wonder') creates the 'I wonder if there isn't ~' = 'wistful wish that maybe there is ~' pattern. The negative wrapping is the idiomatic way to express a wistful hope in Japanese — stronger than a direct positive question would be. The subject of ない is いいこと, and the utterance is addressed to no one in particular.