While charming poet and author Joe Devlin talks about
    working for peace in his native Ireland, he is secretly helping O'Connell
    Industries send arms to the Irish Republican Ammy in Belfast. With one
    breath he renounces his youthful days as a terrorist, with another he
    purchases automatic weapons.
    
    The genial Devlin is signing copies of his autobiography, Up From
    Ignorance, when a man hands him a book with the words "Ourselves
    Alone" printed on the first inside page. He is arms dealer Vincent Pauley
    and this is a signal. "Ourselves Alone" was the rallying cry of the Irish
    rebellion.
    
    But during a meeting at Pauley's hotel, Joe reams that the arms dealer
    is demanding more money. The price of betrayal is death. Traitors must be
    executed. The poet shoots Pauley with one of his own pistols.
    
    As Pauley falls to the floor, he knocks over a bottle of Joe's favorite
    whiskey, Full's Irish Dew. The slogan on the label reads, "Let Each Man
    Be Paid In Full." The mischievous Irishman can't resist making an ironic
    joke. He rolls the bottle near the body.
    
    Lieutenant Columbo visits Joe the next day. The detective has found
    the copy of Up From Ignorance that was inscribed to Pauley. He also
    notices the "Ourselves Alone" message that the author signed over.
    
    Still, Joe claims that he didn't know Pauley. He was just another face
    in the crowd.
    
    The whiskey bottle causes Columbo to suspect Joe. It's the poet's
    favorite brand of liquor. Pauley was a diabetic who couldn't drink, so the
    murderer is someone who drinks Full's Irish Dew.

    And the bottle was moved from the place where it spilled on the carpet.
    Why? It's the type of joke that fits Joe's personality.
    
    Columbo soon reams that Pauley was an arms dealer. The only bit of
    paper found in his room had the number LAP 213. Mrs. Columbo is the
    one who figures out that it stands for Los Angeles Pier 213. That's where
    a vessel bound for Belfast is anchored.
    
    Customs officers and the FBI search the ship, yet no arms are found. It
    looks as if Joe Devlin has outsmarted the authorities.
    
    As the ship is pulling out of the harbor, though, Columbo spots
    something. The tugboat is flying the O'Connell Industries flag, and the
    O'Connells are 10e's very close friends. That's it. The guns aren't on the
    ship. They're on the tug. They'll be transferred to the ship just before it
    puts out to sea.

    Columbo also has figured out something else. The murderer has a habit
    of marking how much he'll drink by scratching the diamond in his ring
    across the Full's Irish Dew bottle. Each time he does this, the murderer
    says, "This far and no farther." Each diamond is unique and leaves a
    distinctive pattern. The scratch on the bottle near the dead man is
    identical to the scratches on Joe's bottles.
    
    The poet accepts defeat by offering Columbo a drink. Well, maybe a
    little, the lieutenant says.
    
    "This far and no farther."
    
    Although Howard Berk's "By Dawn's Early Light" is hailed as one of
    the best Columbo episodes, the writer voices a preference for "The
    Conspirators," the last of the forty-five mysteries.
    
    "Actually, I'm more fond of 'The Conspirators,"' Berk explained. "It's
    more grandiose in its perception. It has a pseudo-political theme that
    elevates it. "
    
    Except for the usual bloating that accompanies most of the two-hour
    episodes "The Conspirators" is a splendid finale for the series. Grins
    masking their deadly serious game, Falk and Revill (the original Fagin in
    the stage version of Oliver!) try to out charm each other. It is a whimsical
    duel between two leprechauns. The weapons are savvy and blarrrey.