In a bid to retain full ownership of the Man of Steel, Warner Bros. filed a brief on Friday asking the 9th Circuit Court of Appeals to reverse a 2008 decision that granted the heirs of Jerry Siegel half the rights to the original Superman story, and to enforce a deal abandoned by the writer's family seven years earlier. If the 9th Circuit chooses not to rule, the studio wants the case to be remanded to a district court for trial.

In its 117-page brief, Warner Bros. seeks to overturn the earlier ruling that terminated the transfer of copyright to the Superman story in 1938's Action Comics #1 under the 1976 Copyright Act. The 2008 decision allowed the Siegel family to reclaim many of the Man of Steel's defining elements, including his costume, Lois Lane, his origin and secret identity -- paving the way for the estate of artist Joe Shuster to do the same in 2013 -- while leaving Warner Bros. and DC Comics with such later additions as Lex Luthor, kryptonite and Jimmy Olsen. As Hollywood, Esq. reports, the Siegel heirs appealed in December 2011, arguing they should have been permitted to recapture the rights in later Superman comics, which they contend Siegel and Shuster created "on spec," and then sold to DC for $10 a page.

The Warner Bros. brief centers on negotiations that began after the Siegel family filed the copyright termination notice in 1999. According to the studio, the heirs "ultimately struck a deal with DC — one that included every essential term for a re-grant of rights, provided for various other non-essential terms, and guaranteed the family many millions of dollars in cash, royalties, and other compensation." But Warner Bros. claims that in 2001, the Siegels were approached by "a self-styled 'intellectual property entrepreneur'" -- attorney Marc Toberoff, who now also represents the Shuster estate --  who convinced them to renege on their deal in hopes of getting even more money.

Although the agreement with Siegel's daughter Laura Siegel Larson and now-deceased wife Joanne Siegel was never formalized, the studio insists "a deal is a deal, long form or not," and therefore should be enforced.

"This long-running dispute should be brought to an end," Warner Bros. says in its brief. "Enforcing Larson’s deal will afford her tens of millions of dollars for which she bargained in 2001,while protecting the deal her own father struck in the 1930s, when DC employed him to create new Superman material on DC’s behalf."