The opening of this arc was very funny (notice the raised S-Shield on the actor ala Superman Returns which the real one doesn't have or the Tim Burton all black rubber Batsuit on the Bats actor) but it fizzled out at the end as it turns out .... spoilers .... the Big Bad is Lana Lang(!) who in her role as LexCorp chairman has been stockpiling industrial strength kryptonite to sell to the military.
When Supes calls to eliminate it, she refuses and says it's necessary for the company and the employees and the LexCorp bottom line ("nothing personal") and then says if he tries anything she'll release the K-Dust in the atmosphere ("don't make me do this") making the Earth too toxic for Clark, Kara, PG, Krypto and Chris Kent to ever live on. He calls her bluff and she stone-faced does it (no explanation on why she destroys her own product that she just said she's only using/needs to make money just to prove a point/poison the man she still loves).
Hiro/KidToyman clears the atmosphere with nano-bots foiling her plans and then Supes harangues Lana that the difference between her and Lois is that Lois would never have pushed the button which is why he married her and not Lana (harsh) and when Supes flies off it's insinuated that Lana has been controlled/maninpulated into doing this. End of story arc. Never really brought up again and obviously not in any kind of continuity because there is no way Supergirl would be rooming with Lana (and taking her last name as her secret identity) in her own book if Lana had really tried to kill her and her entire family. Nor would Lois be seemingly on friendly terms with Lana if she had indeed poisoned the atmosphere and caused Clark to leave Earth for 1000 years (presumably without Lois). Clark would eventually forgive something like that but Lois? Never. But like I said never brought up again after this arc.
So this storyline goes from promising (the scene above) to wall-banging (its ending) very quickly. A big let down for me.