Mon-El gets some bad news in the Robinson, Guedes and Magalhaes story in Superman 688 (July 2009).
The Guardian rescues Mon-El after he falls into the harbour, picking up on the end of the previous issue. Just after he gets fished out, Mon-El is confronted by Squad K and Percy Hazzard. They accuse him of being a Kryptonian, and Kryptonians are currently banned from Earth. Mon-El shows them that he is not a Kryptonian, by taking down the entire squad, to the Guardian’s amusement.
Dr. Light has become the head of STAR Labs, and does tests on Mon-El. She explains to him and the Guardian that the problem Mon-El is facing is his own super-powers. They are battling against the cure he drank for his lead poisoning, interpreting it as an invading virus. She informs the two of them that the lead poisoning will kill Mon-El, within a year to eighteen months.
As Jonathan Kent, Mon-El makes friends with Mitch, a cook at the corner restaurant, who is very chatty, and convinces Mon-El to experience some of the finer pleasures in life.
The Guardian leads his Science Police unit to rescue Tellus, finally. Although they come up against Codename Assassin, they do not actually battle, and Codename Assassin stands aside as the more powerful SP unit escape with Tellus.