CAMBRIDGE — “Tomorrow and tomorrow and tomorrow creeps in this petty pace from day to day” says Shakespeare’s Macbeth, but finally, the waiting is over; tomorrow is here. The Shore Shakespeare Company will present Macbeth, at Long Wharf Park tonight, (May 20) at 7 p.m. A second performance is scheduled for Saturday night at 7 p.m., but may be canceled because of “thunder, lightning or in rain,” (the very opening lines of the play). Macbeth is a play about evil and how it grows in the heart of a man, fueled by ambition and a murderous wife. Witches announce that Macbeth will be king, but he doesn’t wait for time to fulfill the prophesy. He speeds up the process, murdering the good old king. Macbeth and his wife have hands stained with the king’s blood and out of that act come many familiar lines, beautifully delivered by Greg Minihan as Macbeth and Avra Sullivan, his pretty queen with the most evil heart of Shakespeare’s women. How can you not cringe when she monstrously berates her husband and goads him on to murder, saying she would dash the brains out of her tender nursing babe if she had to. But their evil acts put an end to their peace of mind. “Out, out damned spot!” and “All the perfumes of Arabia cannot sweeten this little hand,” yet the killing continues. Having stabbed the king, Macbeth must commit other murders to hide his crime and hold onto the throne. The body count climbs. Macbeth is a psychological study of a man with free will choosing evil and determining his own doom. It comes at the hand of Macduff (Chris Rogers), whose children and wife Macbeth has slain. Shelagh Grasso directs this year’s production, which features Nick Roetzel as King Duncan. Nick lives in Cambridge and has been acting since high school. He played Romeo in college and claims he was admired in his tights. Now many years later, he’s back in purple tights as King Duncan, wears black tights in the parade of Macbeth’s victim-ghosts, and a third pair, gold tights, when he plays an extra lord. Tights can be a challenge to get in and out of, but there’s no challenge for Nick to deliver short-lived King Duncan’s eloquent lines. You almost forget that this outdoor production is an amateur troupe, because the leads are excellent performers. There are small glitches, but with all that murdering going on, you hardly notice. What you do notice is that this production multiplies Shakespeare’s three witches by three, so that many witches are introduced into many scenes, to follow and watch Macbeth. They even skulk around during the poignant soliloquies. It’s the director’s imaginative interpretation, but like wishes, I prefer my witches in threes. I saw my first Macbeth when I was 15 years old. Orson Welles played the movie role on television, and I was transfixed. I learned early that Shakespeare on the page was beautiful language and a little hard to follow at first, but Shakespare on the stage or screen meant very real characters who lived and died teaching you about the good and evil in the human heart. So Cambridge welcomes Shore Shakespeare on this return appearance ... tonight at seven, or tomorrow (Saturday) if it does not rain. Bring a chair or blanket and enjoy the show at Long Wharf.