Clark and his fellow Campus colleagues investigate a connection between an American corporate espionage firm and the North Korean government, who are intent on producing nuclear weapons. In Commander in Chief, he tracks down the accountant of Russian president Valeri Volodin, who has been moving his personal net worth to a safe place in anticipation of his failure to placate the siloviki should his plan of a covert armed offensive across Europe fail to repair the ongoing economic recession in his country. In True Faith and Allegiance, Clark helps investigate a series of terrorist attacks on American military and intelligence personnel, which is due to a massive intelligence breach. He later assassinates a Saudi technocrat who has been setting up ISIS with the attacks in order to save his country from economic ruin in a quagmire likely to result from American troops being redeployed to the Middle East. In Power and Empire, Clark investigates Chinese agent provocateur Vincent Chen's connection to a sex trafficking ring in Texas. He wages a one-man war on the ring in order to save a prostitute as well, who had been instrumental in revealing China's involvement in several false flag attacks designed to blame the current president, whose moderate stance on several issues compelled a secret cabal to act to have him removed from power. Clark was later arrested for murder, but was released from police custody soon after. Clark briefly appears in Line of Sight, where he assassinates a Romanian crime boss who had a vendetta against Jack Ryan Jr. in revenge for killing one of his associates in a previous novel. In Oath of Office, Clark leads a surveillance operation in Portugal on French arms dealer Hugo Gaspard, who has ties to ISIS. He witnesses Gaspard's murder by French assassin Lucile Fournier, who works under rival arms dealer Urbano da Rocha. Clark and his team then proceed to shadow Da Rocha and Fournier, who later strike a deal intended for Gaspard with a pair of Russian GRU officers. However, the Russians later double cross da Rocha, attempting to kill him in his villa. Clark rescues the arms dealer, who later reveals a plot to provide stolen nuclear weapons to dissident Reza Kazem on behalf of the GRU and the Iranian government. In Code of Honor, Clark leads the Campus's efforts to retrieve Calliope, a next-generation AI software, before the Chinese military uses it