Albert and Lisa continue to be suspicious of Curtis, whilst Lifeline is stretched to its limit trying to deal with several evaders. The Germans capture one evader, Sergeant Walker, who has travelled down the line and is familiar with several of Lifeline’s personnel. Walker makes a desperate bid for freedom to avoid talking and throws himself down a staircase at Gestapo headquarters. As Walker recovers in hospital, Lifeline deliberate over whether he can be rescued from the Germans or if he must be silenced to preserve the security of the line.

The Jewish population of Brussels is being systemically deported according to colour-coded identification papers developed by the Germans. Curtis becomes involved with a Jewish family hiding out in the city and asks Lisa if Lifeline can help, but Lisa is unwilling to put the line, which is supposed to help RAF evaders not Jews, at risk. Curtis himself is still under suspicion by Albert, when Lisa’s uncle, bank manager Gaston Colbert, identifies Belgian banknotes he brought over from London as forgeries. Kessler obtains some of the notes, and realises that they are too accurate to be real and have been made by the Belgian treasury plates, which were evacuated to London before the German invasion. He believes that the notes will bring him closer to Lifeline.

The safety of Lifeline is at risk when Albert deduces that the Candide is being watched by a Gestapo spy, while Lisa continues to resent Curtis’ presence and his domineering take-charge manner. A wounded RAF evader, Finch, finds sanctuary with Hans Van Broecken, a Dutchman who lives on a barge with his wife Lena. Finch plans to desert the army and escape to Switzerland and finds a kindred spirit in Hans, who is in fact German and deserted during the First World War. Hans plans to take Finch to Switzerland himself on the barge, but Lifeline becomes involved when Lena receives a visit from her niece – Natalie. However, helping evaders escape to comfortable Swiss internment is not Lifeline’s purpose, and how can Finch be involved with Lifeline with the Candide under German surveillance?

The citizens of Brussels are ordered to celebrate the Fuhrer’s impending birthday, and Albert and the others are suspected of being collaborators when they must hang a Nazi flag outside the Candide. Meanwhile, a man claiming to be an RAF evader approaches Catherine Bidout, an elderly English woman who has not yet been interned by the Germans. Rumours of a British woman in Brussels hiding an evader reaches the Candide and Albert decides to investigate. Madame Bidout is uneasy about the risks she is taking and contacts an old friend – Brandt – for help. However, the evader is a plant placed by Kessler to entrap Lifeline and now Brandt is also in danger.

As Easter approaches, a monk from a local order, Father Girard, visits the Candide to hear Andree’s confession and also overhears a conversation about an evader. He offers his assistance to Lisa, who gratefully agrees that the airman can be hidden in the abbey over Easter. At the abbey, the head of the order, Father Pierre, is happy to help Lifeline, however another of the brothers, Brother Anselm, strongly believes that the order should not endanger itself by getting involved with the resistance and misguidedly contacts Kessler.

Curtis’ cover has been blown and Kessler knows that he is part of the resistance. To avoid endangering the others, Curtis goes to ground in Brussels. Knowing that Lifeline is at last in his sights, Kessler orders that all routes out of the city are blocked and co-ordinates a house-to-house search throughout the city. In desperation, Curtis goes to the Candide to ask for help, and Monique comes up with a highly audacious escape plan.

Dr. Keldermans visits the Candide with tragic news, and Albert must take decisive action if Lifeline is to continue. Meanwhile, Natalie has the difficult task of taking two eccentric Russian evaders down the line. Brandt dines with a high-ranking military acquaintance, Oberst von Elmendorff, who tries to recruit him in a military plot to assassinate Hitler, while Kessler invites Albert to a strange garden party.

Whilst dining at the Candide, Kessler becomes intrigued by Madeleine Duclos, an elegant but remote socialite. Meanwhile, Monique takes some airmen down the line and is shot and wounded when she becomes unintentionally involved in a smuggler’s attempt to evade a railway checkpoint. Recovering in a convent hospital, she is cleared of smuggling, but finds herself in more danger when the French police discover the train tickets she was carrying for the airmen and that her papers are false. Kessler sets out from Brussels to interrogate her, prompting Natalie, Alain and Max to stage a daring rescue mission.

Hoping to boost Lifeline’s flagging funds and gain some independence from London, Albert and Monique concoct a plan to sell three valuable Rubens paintings, replacing the originals with forgeries. However, Kessler is also aware of the paintings’ existence and plans to acquire them for Germany, setting out to remove them from the convent near Antwerp where they are held. Meanwhile, two American evaders, impatient with Lifeline’s security checks, decide to strike out on their own and ambush the car that Kessler is travelling in. Totally unaware of the true identity of their hostage, the Americans and their captive impose themselves on Hans and Lena Van Broecken, demanding that they are taken to Switzerland on their barge. Lifeline must not only retrieve the paintings, but also ensure that no harm comes to Kessler, as horrifying reprisals by the Germans are at stake.