Mattes rushes to a reported theft after the extra pieces for a Brazilian expo are unpacked in Hamburg Maritime Museum by curator Bernd Koberstein. Checking the crates Mattes get bitten by a red-white-black-striped serpent, soon identified as the deadly coral snake, yet despite the zoo reptiles expert catching the snake and finding its fangs emptied, no real symptoms occur: there must be another victim, possibly the man who rudely rushed by, nearly toppled, senior regular visitors Dieter and Käthe Krieger. A fainted patient fits the bill, but that's only half the plot. Meanwhile Hans bought juvenile friend Lothar Huse's too cool bicycle, which Wolle allows the knave to use.

The unidentified hoodie wearer who tried to steal a rock guitar from busker Jan Zöller, who incurred a bad head injury, tries again when it's evidence in the police car, but is chased away by Hans. He handles the case with special input from captain Martin Berger, a Beatles fan who recognize sit's the type used by John Lennon at his Hamburg concert, and even involves his friend Johnny Winter, who runs the Beatlemania museum, for authentication there by expert Florian Hubbe, Mattes being assigned to guard it. While Hans checks on Jan having got it from a forgetful old Mona Trinklein, whom he cares for as social service volunteer, who ran a boarding house used by budding artists like the Beatles at heir first visit to Hamburg, the ruling as not Lennon's own is discarded and the culprits identified.

After anonymous threats, which Mattes and Melanie came investigate routinely, haughty theater director Jens Harting falls badly, not fatally, before their eyes through a stage trap. Suspects are the Romeo and Julia cast, especially the leads Timo Knof and Anna Liska, and stage crew, including prompter Kupfer. Wolle is in annual murder mood during spring cleaning, snapping at Tarik and Claudia.

Tax adviser Michael Otterberg is mugged while driving with his lover Katja Sorensen in his luxury car, which is stolen and seems his main concern. Tariq discovers there was a small wave of such thefts, apparently linked by a 'geo-caching' (treasure hunt with geo-navigation) site and sets out tracking down the game clues-riddled trail, looking for crime clues.

Answering a landlord's call, Tarik is shocked how rudely he expels and plans to search an old man, who is later brought in ER. He may have to reconsider as drugs are found in his reclaimed room. His daughter and grandchildren are surprised by his poverty, culminating in homelessness, having assumed he refused to help them out as a scrooge. The real drug crooks are found, Finn regrets having rejected his grandpa's make-up heirloom offer. Meanwhile Wolle is wrongly accused of loosing the memory-stick captain Martin Berger stored his hard-prepared seminar on, without backup.

Not only does senior officer Hans Moor arrive atypically late at the precinct with a hangover and blackout -even forgot his car- after a party night, there are indications he may be involved in the disappearance of whore Paulina Kowalczyk, whom housemate Ilona Herwig reports missing. While IA officer Rainer Voss -again- gets him ordered off the case, treated as sole suspect given a bar brawl and blood traces, Hans is hell-bent to find the link with an earlier incident, when businessman Peter Gerold failed to bribe his son out of prosecution for drunk driving. Pressed for time, the team finds more, linking Gerold to an earlier scandal and the harlots.

August Gradka steals a van in front of his employer Anita Berens, who gives chase, resulting in a crash and her ER-admission. He's a gentle halfwit, living with his mother Irene. The drugs found inside don't fir his profile, but big brother Manfred, a drug dealer, who seems in league with drug lord Zak Maatouk, who was recently paroled or good behavior but immediately reactivated his gang. The team gradually discovers plot twists and surprising motives.

Mattes is stunned that Melanie plans to spend six holiday weeks in a Nepalese Buddhist monastery. They must investigate the stolen proceeds of socialite Van Oppen's latest foundation fundraiser at her villa. PA Henner Höhne and housekeeper Elfriede Kern had ample opportunity, but the former reports a mystery man slipping away, who apparently left behind a flower bouquet. Franzi's husband Dr. Philipp Rost demands proper arrangements for their kids. Hans and see are called about fighting, injuring charge Tomek, and other mischief at Jochen Kreuzer's alternative problem youth program. Kreuzer visited Van Oppen, or rather Höhner, needing a donation, spotted and reported by Kern, but the flowers were bought by a knave.

Ambulance Dr. Philipp Haase is out of whack, incurring another minor injury and unwilling to get standard treatment from hospital's ER chief. He advises hypochondriac patient Heinz Heuer, who wrongly believes to have terminal cancer, a psychosomatic clinic, in vain. Heinz is wrongly presumed to be the Internet soulmate -using pseudonyms- of cow farm girl Mäggy, who came to the city fearing he's suicidal.

Banker Jonas Wittkamp was badly wounded, unlike his passenger girlfriend, when a stolen car crashed his. Tarik, Hans and Claudia trace the car owner and victim to countess Marisa von Schmetting's wine dinner and etiquette course, which she and/or accomplice Martin Brandauer abuse to rob rich clients. .

Hans is shocked to recognize former lover Ines Hauber, who fled Hamburg having witnessed mobster Tommy Prokop in person shooting his own attorney. As her witness protection proved leaky then, Hans agrees to cover for her informally, stretching Tariq and other colleagues' loyalty by expecting them to withhold legally obliged collaboration to court protection officers Thorsten Schneider and Rainer Voss. Ines returned for her old, ailing 'second mother', who is found slowly arsenic-poisoned in her home.

Tariq fuzzes how to testify -a first for him- in court in the domestic abuse case against Maik Bärmann, whose medical friend supports his denial to beat his wife Ina and cruelly punish their two kids. The case is delayed as ER doc Jasmin doesn't turn up to testify, which worries the team, especially Tariq and her uncle, captain Martin Berger. Ina leaves the women's shelter and withdraws her charge, which was never supported by her own mother, whose part must be clarified, while Jasmin was locked up in the Bärmann cellar and talks in to the trio.

Motor vehicles dealership owner Holger Lohmann was victim of a hit and run, drunk after his bachelor party. His prize car was joy-ridden by an insider: someone removed the security camera, which proves worth searching. All guests, including staff, are checked by Mattest and Tarik's patrol duos. Best man Andi Becker is suspiciously close with bride Sybille Schulte.

Three masked robbers stole 380.000 Euros life savings with semi-retired movie star Elisabeth Hohenfeld's forced, soon dumped -with private affairs- home safe and knocked her on the head -mildly- when she caught them at night. Tarik suspects the culprits knew too much, so probably live near her villa. Main suspects include housekeeper Elfi Schmidt, adventurous life partner sailor Robert Fröhlich, whose fingerprints are found, and sister's adult orphaned son Adrian Hohenfeld, who used a voice modifier to call an ambulance anonymously and still has urgent loan shark trouble as Emir Kostun's goons found the safe empty. Fan Wlle stumbles on a clue to Esiabeth's own sneaky part in the criminal debacle.

Professional tango dancer Ramona, a transsexual born Ralf Hellwig, is brought to ER badly beaten up by a masked man near the Hamburg rowing club, where he was long a member with buddy Andreas Wiegand. It's presumably a hate crime, which even macho Tariq has difficulties situating, but the victim refuses to speak up. His employer, dance school owner 'Eduardo Esteban', has his own dark secrets. Ralf's adult son Carsten Waits was completely estranged, moving to the US on school exchange from age 18 and is visiting Hamburg, now a pilot in Arizona. .

Novel apprentice Annemarie Kleinert is shortly hospitalized after a fire at one of the cheap barbershops run as a chain by Gregor Krantz, who exploits un(der)qualified staff, promising them a 'training' without value, and may be practicing insurance fraud as he's in debt. His rival Leo Faber can't compete with those dumping prices, despite superior quality and innovation, like the new die developed by his pet apprentice Micha. Motives and opportunities abound, but another crime exposes the truth bluntly. Claudia's adult son Max Fischer visits fro the weekend and treats the precinct to his handyman skills, well beyond Wolle's.

Bike courier Marvin Färber was beaten badly on the street, so goes to ER, but also worries about his missing teen sister Mona, who is object of anonymous blackmail threats, and app-tagged. Marvin's slick boss Leonidas Bracht is Mona's dodgy lover, but has an alibi. Father Klaus being a poor provider, Mona and kid brother Tim are desperate if Marvin leaves, having got a Berlin scholarship. Tariq is shocked that patrol partner Claudia isn't unconditionally supportive for her in-living ex-con son Max.

Caught after allegedly mugging Corinne Blume outside her apartment, 'culprit' Gerd Jankowitsch, who got wounded by her and is found in agony on her staircase, insists it was part of a sex game they agreed to by Internet, which is openly recorded on the kinky dating website. Even ER nurse Frauke fears Blume, her strict former high school teacher, whose reputation at school is wrecked as pupils get wind of her 'caning alter-ego', she maintains she was set-up by an impersonator. Prime suspect Alina Schubert admits only to car vandalism, but later threatens Blume and Franzi with dangerous chemicals, wrongly believing her useless mother Nadine's life was wrecked by Blume. Mattes finds the real, adult impersonator through the dating site.

Ein schlechter Morgen für Franzi: Heute ist ihr Hochzeitstag, und nichts läuft nach Plan. Emma "verschönert" ihr Brautkleid bis zur Unbrauchbarkeit, und ein Ersatzkleid gibt es nicht.