On the run from the police, S.S. Kumar (Dharmendra), a thief, comes across a private invitation to the island of Sir John Locksley (Sir Rex Harrison) addressed to Raja Bahadur Singh (Prem Nath). When the Raja is shot, Kumar takes him to a nearby hospital, dons a Sikh's turban, poses as the Raja's son and goes to the private island of John. Also attending are K.P.W. Iyengar (O.P. Ralhan), Dr. Bukhari (Shammi Kapoor), Colonel Columbus (John Saxon), and Countess Rasmussen (Sylvia Miles). A stunned Kumar finds out that all of these invitees are master criminals and gangsters. Kumar's guise does not fool anyone, including his former sweetheart, Sheila Enders (Zeenat Aman), nevertheless John permits him to stay on, as he feels that Kumar's career, though an amateur, is consistent with those already present. The reason why John has invited them is to find a successor to take his place as he is dying of cancer. He feels that one of his invitees can be trusted to take his place and for this he has arranged for them to steal a diamond (shalimar) worth one hundred thirty-five crores of rupees. This gem is placed in a secure place within his palace, which is alarmed, and guarded by armed men twenty-four hours a day. He challenges one of them to steal the shalimar, but if anyone fails then he or she is killed instantly. Pitted against such veterans, it looks like Kumar has gotten himself into a bind out of which he may not come out in one piece.