Johanna Pasquali est une jeune femme qui n'a qu'un seul rêve dans la vie : intégrer le RAID, au grand désespoir de sa famille. Jusqu'à présent policière dans un commissariat, elle tente une nouvelle inscription au RAID, mais échoue, à la grande satisfaction (cachée) de son fiancé un peu falot, de sa future belle-mère (épouse du leader européen du pneumatique) et de son propre père Jacques Pasquali, ministre de l'Intérieur. Il faut dire que malgré son côté courageux et sans peur, elle est très gênante et maladroite.
En Basse-Bretagne, Hélène Jégado est une enfant isolée, surnommée « Fleur de tonnerre » par sa mère. Enfant, elle est terrorisée par l'Ankou, personnage mythique de la mort. Après la mort de sa mère, Hélène devient domestique. Pour surmonter sa peur, elle décide qu'elle est l'incarnation de l'Ankou. Hélène va devenir la plus prolifique tueuse en série française.
Julien, créateur d’applications pour mobile tombe amoureux d'Eva, une jeune journaliste. Suite à la demande en mariage de Julien, Eva doit lui présenter ses parents résidents sur l'île de Ré. Tous se retrouvent lors d'un week-end qui sera mémorable pour chacun d'entre eux.
L’Eyjafjallajökull, volcan islandais, est en éruption, entraînant une paralysie du trafic aérien européen. Pour Alain et Valérie, un couple divorcé, c’est une catastrophe. S'ils veulent arriver à temps au mariage de leur fille dans un petit village de Grèce, ils devront faire la route ensemble quitte à se supporter.
Romain Faubert is a mature man who can never hide his hypochondriasis. Romain's fears are profitable for his doctor Dimitri Zvenka. Even so, Dimitri really wants to cure the patient who has no other friend than him. He feels that Romain's actual problem is his loneliness rather than anything else. He subsequently helps Romain in seeking an appropriate female companion, but after a great many futile attempts, he loses hope that Romain could ever succeed. In need of an alternative, he decides to take Romain with him when he goes to an eastern European refugee camp (refugees speak, in fact, Ukrainian), where Dimitri sometimes works on behalf of a non-profit organisation. He believes the sight of people who are really suffering might bring Romain to his senses. Yet Romain finally finds the love of his life when he gets to know Dimitri's sister who confuses him with Anton Miroslav, a certain freedom fighter. The real Anton Miroslav has stolen Romain's ID and is hiding in the apartment of the hypochondriac.
Isabelle (Diane Kruger) is prepared to marry Pierre (Robert Plagnol), the man she has loved for the past ten years. First she has to overcome a curse that her female family members have been battling for years—that all their first marriages end in divorce. Isabelle comes up with the perfect plan. She will marry a stranger and get a quick divorce to avoid the curse and be happily married forever the second time. She flies to Copenhagen and finds the perfect pigeon in Jean Yves (Dany Boon), an editor for the Guide du Routard, but her plans are complicated when he believes that she is in love with him. When Isabelle's arranged marriage goes awry, she tracks down the pigeon in hopes she can somehow marry him and divorce him without too much trouble. When he travels to Kenya, she follows him in the hope that he will sign her divorce papers.
Philippe Abrams is the manager of the postal service (La Poste) in Salon-de-Provence, Bouches-du-Rhône, in southern France. He is married to Julie, whose depressive character makes his life miserable. Philippe does everything to get a job at an office on the Mediterranean seaside to make her happy. As this favourable position will be granted to somebody who is disabled, Abrams decides to pretend that he is. However, the management finds out. As punishment, he is banished for two years to Bergues, a town near Dunkirk in northern France. Northern France – and the Nord-Pas-de-Calais region in particular – is considered "the sticks" – a cold and rainy place inhabited by unsophisticated ch'tis who speak a strange language (called "ch'ti" in local parlance, and "cheutimi" in the South). He has to spend his first night at Antoine's place, a co-worker of his. Philippe initially dislikes Antoine for his rude behaviour and because he thinks Antoine is gay (he found photographs of Antoine dressed as a woman, but they were taken during a carnival party). However, later in the film, Antoine and Philippe become best friends.