Complex sentence: Spender goes to Syndicate headquarters, only to find Krycek, who tells him that the Syndicate members are preparing to present the alien fetus to the aliens--except for The Smoking Man, who has gone to retrieve Cassandra.
Split into simpler sentences: Spender goes to Syndicate headquarters, only to find Krycek. Krycek tells him that the Syndicate members are preparing to present the alien fetus to the aliens--except for The Smoking Man, who has gone to retrieve Cassandra.