With the password "Tweng", Captain Zeppos enters a strange house. Marleen, the secretary, brings him to her father: Mr. Elias. Zeppos is given is a mission to shadow Cara Wilmers, also known as Aunt Cara. The Captain refuses to do this without further explanation. Meanwhile in the park, Ariane overhears a conversation between Aunt Cara and a stranger. It makes Captain Zeppos and Ariane very curious about "Tweng".

At Aunt Cara's home, Ariane and Captain Zeppos meet Mizernak, Aunt Cara's Russian friend. A short while later, Mizernak arrives at the Mill Cottage with a wounded hand. Captain Zeppos and Ariane get even more curious. Could Aunt Cara be a spy? Ben also gets acquainted with "Tweng" - a stranger brings him to the station where he meets Brenda, who is in serious trouble.

In his search for "Tweng", Captain Zeppos arrives on a film set. At last, he gets an explanation about the purpose Mr. Elias' organisation. With the help of Captain Zeppos he wants to fight peace-threatening forces, like the SABOS organisation. SABOS, or the mars men Captain Zeppos saw at Overslag, could be very dangerous.

When Captain Zeppos and Aunt Cara arrive at the Mill Cottage, both horses and Ariane are gone. They find Gust who has seen the abduction of Ariane and Mizernak. Captain Zeppos goes on a search and he finds Ben, who also got kidnapped but was able to escape. Zeppos finds Brenda's story very intriguing. In the meantime, Ariane is held prisoner at the SABOS headquarters. They question her to find out about "Tweng".

Episode 5
Wednesday 8th January 1969, 4.00-4.30pm

Ben and Marleen visit Brenda's flat. Ben's suspicion that Brenda is involved in the kidnap plot grows stronger. When he meets her in the barn of the Mill Cottage, he isn't a bit confident of her good intentions. She tells him she fled from SABOS. Meanwhile, Captain Zeppos shadows the man who contacted Ben, and Ariane tries to escape from the SABOS headquarters.

Thanks to her SABOS disguise, Ariane is able to escape. Together with Captain Zeppos, Ben and Brenda, she tries to find the location of the SABOS headquarters. The search is in vain, and Ben is saddened by the loss of Brenda during the attempt. But Captain Zeppos has little confidence in her.

Episode 7
Wednesday 22nd January 1969, 4.00-4.30pm

Mizernak is on the run from Ben and Marleen. Brenda and Captain Zeppos meet Rufus, a regular customer in Aunt Cara's antique shop. Captain Zeppos reports this meeting to "Tweng" and Mr. Elias confirms the Captain's suspicion: Rufus is the prime suspect. He is not only a collector of antique army equipment but also a major in an African mercenary army.

After a long search, the SABOS headquarter is found. Mr. Elias brings the complete "Tweng" organisation into action to overpower SABOS. Captain Zeppos is proved right about Brenda - she turns out to be the right hand of Rufus, the SABOS leader.